Where to buy prepaid electricity from Eskom online with your credit card [Solved]

Here’s an updated posting offering alternatives to PayCity that has now stopped selling prepaid electricity.

My previous article “Buying electricity via mobile cell phone or online” listed many ways of purchasing prepaid electricity online and with a credit card. 
Most online sites offer the service for free and you still get your free units per month.
I was looking for a service where I could purchase electricity (for no extra charge) using my credit card.
I wanted to be able to use my PC or my cell phone's browser or use SMS to purchase.

Using my credit card is much more convenient (no more queuing for cash, and for purchasing the electricity), and so it's safer too! [those ATMs are becoming dangerous]

Additionally, if I run out of electricity in the middle of the night then I can purchase more by sending an SMS from home.
Oh, and the cherry on the top is that the bill comes at the end of the month along with "reward points" and even cash back discount.

Here is an updated list of sites that I’ve found that cater for City of Cape Town electricity:
My preferred choice, after analysing all the options that I could find is Powertime.  Their offering seems the most complete, with apps for most mobile devices as well as a nifty web site with add-ons like virtual meter and a graphical analysis of your electricity usage, and lots of energy saving tips.
A couple of emails to their support email address relating to credit card fees were answered quickly and with the requested information (and more).
Powertime’s web site warns that purchasing using your credit card could attract a fee “… between 0% and 5% VAT inclusive of the transaction value”.  An email query later, and I found out that this service fee depends on whether the municipality reimburses credit card costs or not.  It turns out that there is no service fee for Cape Town meters.  To be sure, send them an email with your meter number and they will confirm the service fee.  
Note that the purchase of electricity in Cape Town has to be done via SMS due to restrictions set by the municipality.
You can setup SMS vending on the Powertime website in: “Electricity” –> “Buy Electricity” –> “Set up SMS vending” section.
(EFTs are all free of charge. )

The service is available 24/7 via the following channels:

• Powertime Web site www.powertime.co.za or mobi site m.powertime.co.za,
• iPhone, iPad, iPod Touch Powertime applications which can be downloaded from Apple App store on iTunes (http://itunes.apple.com/app/powertime/id345272537?mt=8 or search for Powertime),
• Android Powertime app, which can be downloaded from Google Play https://play.google.com/store/apps/details?id=com.methys.powertime or
  the Samsung Android app store: http://www.samsungapps.com/topApps/topAppsDetail.as?productId=G00002564713
• BlackBerry Powertime  application on the RIM App store: http://appworld.blackberry.com/webstore/content/11271
• Nokia Powertime application which can be downloaded from the Nokia app store: http://store.ovi.com/content/105666

On these channels, you can use Visa, Diners and Master Card credit cards or the PayGenius wallet, which can be recharged by EFT or credit card. You can also use Debit cards as well on the Powertime Web site.
Twitter: @powertime_za and Facebook
You can also pay your other municipality bills and cellular airtime too.
You can even make some money by referring your friends to Powertime – Login, then follow the “Refer a friend”  link to send your friend an email.  When they spend their first R350 on electricity, then you will get R30 in your PayGenius wallet :)

Here is some more info on Powertime: 
https://moneysmart.co.za/community/2012/06/save-electricity-and-save-money-with-powertime
http://ventureburn.com/2013/03/the-city-of-cape-town-cant-keep-a-good-startup-down-powertime-is-back


Another company that offers purchasing prepaid electricity online and using SMS is ItronEnergy.


FNB mobile: dial *120*321# from your cell phone and navigate thru the menus.

https://new.easypay.co.za/bmeter.aspx

www.ibuy.co.za you can save your setting so that you can easily buy from your phone (no fees, as far as I can see):


Other options:
EFT only - no credit card: PrePaid24.co.za
MyPrePaid.co.za
PrePaidElectricityMeters.co.za
PrePaid24Galore.co.za
PrepaidXtreme.co.za
PrePaid24Online.co.za


http://www.cellpower.co.za/consumer
 
No credit card purchases, but EFTs are processed under 5 minutes (24/7). Also offers airtime.

The winner of the “no contract, pre-paid data deal” in South Africa is… CellC!

I was looking for a data deal that doesn’t attract monthly charges since I don’t use my iPad away from home very much – ideally, the per MB rate should also be lower than the R2/MB out of bundle rates that Vodacom and MTN offer.

I had my eye on the much-advertised-to-me offer from FNB.  I was prompted to investigate further when I saw a tweet to FNB asking for clarity on the FNB deal (first 50 MB per month at 30c/MB, thereafter 59c/MB).  The pre-requisites for using this deal was listed as “A Vodacom Service Provider contract (excluding alternative service providers like AutoPage, Nashua Mobile, etc.) Or alternatively, any MTN cellphone contract”.
So, if I wanted to take up this offer, then I would need to take up a cheap contract that would attract monthly charges, and then the per MB rate would be low.

Here are the Twitter conversations:
 



 


@TopEditorInt warned against contracts – I tend to agree with that… so, I looked further…


I needed to answer the question: “What was the best per MB rate that I could get without taking out a contract, and where the data wouldn’t expire in a month or two?” 

{
Note: this posting has been updated and edited since it was first published… VirginMobile was my original choice (until I found out the their packages expired after 30, 90 or 120 days), the modified “winner” is CellC
}

So, the search was on… perhaps a small monthly fee for a contract from MTN or VSP (Vodacom Service Provider) with a small amount of data could be topped up with data from FNB?  So, I checked all the web sites and compared them.  Bear in mind, I really didn’t want a monthly fee since I hardly used my iPad away from WiFi for more than once or twice per month.

Vodacom data deals list had “MyMeg 10” deal on offer (90c per MB) – but those aren’t contracts so I wouldn’t be able to topup with the FNB deal :(  These were valid until the end of the following month.

MTN data deals list had “MTN-10MB” deal on offer (R1 per MB)– but those aren’t contracts so I wouldn’t be able to topup with the FNB deal :(

CellC data deals list had “25” deal on offer (80c per MB) – but those aren’t contracts so I wouldn’t be able to topup with the FNB deal :( 
These were valid for 30 days.

8ta data deals list had “100” deal on offer (40c per MB) – but those aren’t contracts so I wouldn’t be able to topup with the FNB deal :(
These were valid until the end of the following month.
VirginMobile data deals list had a flat rate of 60c per MB – but those aren’t contracts so I wouldn’t be able to topup with the FNB deal :(
These didn’t expire! Plus: you get R10 for every R30 used.
Plus: DOUBLE YOUR AIRTIME on your first recharge: That takes the rate down to 26c/MB

You get the recharge amount immediately.  The first 50% of FREE airtime will be loaded within 24 hours.  A calendar month later you will receive the next 50% of FREE airtime. e.g. If you recharged with R300, you receive your R300 + R150 (50% of the first recharge free) and a calendar month later, you’ll receive another R150 (balance of the 50%) free.



So, if you bought R300 for your first purchase, that would get you a rate of 26c per MB – that’s even better than the “special” FNB deal, and there’s no need for a contract and no monthly fees, and no expiring/lost data! 

After the first recharge, the per MB rate goes up to 45c – still not too shabby:


So, the clear winner of this competition is: well…. not so sure any more… Waiting for VirginMobile’s response to my Tweet (see explanation below)
With this hurdle, I decided to look further into the other offerings more closely… and I found this winning deal from CellC: 3GB Valid for 365 days (SIM card only – no modem) for R399 once off!


The CellC offer works out to 13c per MB, R133 per GB, or R33 per month, and 250MB per month – perfect!  I don’t think I’d use that much but hey, what a winning deal!

Comparing this with the original “winning” VirginMobile offer even with the ‘Double your airtime on first recharge’ I would only get 1.5GB at 26c/MB for R400!  So, I will get double the bandwidth that won’t expire after 120 days.

Comparing that with the FNB offer of 30c/MB then 59c/MB – it just plainly blows that out of this universe!



Now, where can I go and get one of those CellC microSIMs from?:  http://www.cellc.co.za/cellc-stores

Oh, and yes, you can purchase CellC airtime from the FNB Internet Banking web site :)
BUT, the 3GB for R399 deal can ONLY be purchased at any CellC shop.


Call CellC on 084 140 (Available 24 hours a day, including public holidays)
Twitter: @CellC
Find your nearest CellC store here: http://www.cellc.co.za/cellc-stores  Remember to take your ID and some sort of proof of address eg: Edgars account, or municipal account.
I wonder how much their MicroSIMs cost? {From comments: R29 incl VAT)

Thanks to the original Tweeters for prompting me to do this investigation!

Please let me know if you have found a better solution to this by adding your comments to this post.


Update 30 Apr 2012: Just got a response from VirginMobile to an email – the MicroSIM cost 99c (not like Vodacom’s that cost R110) and can be obtained from any VirginMobile store.

Update 01May2012 08h00: So, I went into a VirginMobile store and wanted to confirm my findings.  I wanted to confirm with the salesman that the Virgin Mobile airtime didn’t expire… but, to my surprise he showed me a brochure with a table of how long the airtime lasted for before expiring – so, it seems that VirginMobile airtime does expire:

How frustrating – I had done all of this research on the web site (and awarded a “clear winner” to VirginMobile) only to find out of this obscure “expiry period”! 
BTW: I searched long and hard on their web site and couldn’t find any reference to the expiry period – hopefully @VirginMobileSA will reply to my tweet.
So, I decided to rename the title of this posing – I removed the “non-expiring” phrase, so as not to mislead you my readers… and now I need to decide whether to award my winning provider to one of the other networks?
If I decide to go with another network then they certainly will not be the winner of this “competition” – watch this space for my decision…

Update 01May2012 18h45: I have updated the post with further investigations and I have decided to go with the CellC offer – so, the clear winner of this competition is: the CellC 3GB for 365 days offer

Buying electricity via mobile cell phone or online [Solved]

There’s only one thing that I hate doing more than putting petrol in my car – that’s buying electricity… the pain of drawing cash, then going to the local cafe or garage to get that electricity token is sooo painful!  But that was until I found other ways of buying electricity without even getting into my car :)
 
You still get your free units per month and there are no extra costs.

Most of these sites allow you to purchase using your credit card.

After registering I can now purchase electricity (for no extra charge) using my credit card. I can use my PC or my cell phone's browser or use SMS to purchase.
Using my credit card is much more convenient (no more queuing for cash, and for purchasing the electricity), and so it's safer too! [those ATMs are becoming dangerous]
Additionally, if I run out of electricity in the middle of the night then I can purchase more by sending an SMS from home.
Oh, and the cherry on the top is that the bill comes at the end of the month along with "reward points" and even cash back discount.


Here is a list of sites that I’ve found that cater for City of Cape Town electricity:
FNB mobile: dial *120*321# from your cell phone and navigate thru the menus.
 

https://new.easypay.co.za/bmeter.aspx    

www.energy.co.za     (not accepting new registrations)


www.paycity.co.za    
(Via SMS: SMS "secret code cvv amount" to 41658 to buy electricity)

www.powertime.co.za [currently offline for Cape Town electricity purchases] register meter number and pay by credit card.


http://www.cellpower.co.za/consumer   No credit card purchases, but EFTs are processed under 5 minutes (24/7). Also offers airtime.

www.ibuy.co.za you can save your setting so that you can easily buy from your phone
 


http://www.prepaid24.com/index.php?comp=content2&page=electricity
  There’s even a lucky draw and you could win your electricity for free (PowerWinna)



Outside Cape Town: 
http://www.prepaidelectricitymeters.co.za/# 
http://www.prepaidmobionline.co.za/municipalities.html

Discounted airtime for your cell phone – where’s the best price?

It’s been a while since I updated my “Buying Airtime Calculator” calculator (Feb 2009), so I decided to do another Bing search (anyone noticed that I’m avoiding Google?).  Truth-be-told, I was spurred to update the calculator after I saw a Tweet from @HifiCorp: “Now you can talk for more while paying less with our discount prepaid airtime offers! http://bit.ly/l2Q3Zz”.  The link takes you to a very large pdf file – I’ve snipped the great pricing:

Or in tabular form from the calculator here:

	Vendor	CreditCard	Date	Airtime Value	Actual Cost	Discount
Vodacom	HiFiCorp	Yes	Jun-11	5.00	4.70	6.00%
Vodacom	HiFiCorp	Yes	Jun-11	12.00	10.90	9.17%
Vodacom	HiFiCorp	Yes	Jun-11	29.00	26.90	7.24%
Vodacom	HiFiCorp	Yes	Jun-11	55.00	49.90	9.27%
Vodacom	HiFiCorp	Yes	Jun-11	110.00	99.90	9.18%
MTN	HiFiCorp	Yes	Jun-11	5.00	4.60	8.00%
MTN	HiFiCorp	Yes	Jun-11	10.00	9.30	7.00%
MTN	HiFiCorp	Yes	Jun-11	15.00	13.90	7.33%
MTN	HiFiCorp	Yes	Jun-11	30.00	28.50	5.00%
CellC	HiFiCorp	Yes	Jun-11	5.00	4.60	8.00%
CellC	HiFiCorp	Yes	Jun-11	10.00	9.30	7.00%
CellC	HiFiCorp	Yes	Jun-11	25.00	22.70	9.20%
CellC	HiFiCorp	Yes	Jun-11	35.00	30.80	12.00%
CellC	HiFiCorp	Yes	Jun-11	50.00	45.50	9.00%

Download the updated calculator which also lists the outlets that I could find here:  http://www.mediafire.com/file/l6bq6ioa44wwl7q/BuyingAirtimeCalculatorJune2011.xls

Anyone notice that they don’t list the new provider 8ta?  Do they even sell 8ta airtime?

That’s not just a question “out of the blue”… I’m getting suspicious about why GoogleAdsense suspended my account almost immediately after I posted this article on 8ta’s “special”: ‘I knew there had to be a catch with that 8ta deal for a Blackberry for R90 per month.... with free calls to a landline number’.
8ta was an advertiser on my blog – in fact the questions that I received were from readers asking about “my ad” on “my blog site”.
Since Google Adsense will not tell me the reason(s) for the suspension I will continue to speculate – and believe that this is the reason.

PrePaid airtime offers not to be missed: R400 gives you R1,176 airtime (VC), or R800 for R2,400 (MTN), or R800 for R2,760 (CellC)

Here’s an airtime offer that seems too good to be true!  MTN and CellC have also thrown in some free SMSs! Pay these once off fees with no credit check and get lots of free airtime.  This seems to be a fantastic offer!  What’s the catch??  If you’re on a VodaGo prepaid account, on the old per minute billing, then I see this is a per second billed plan… so the per minute cost is probably more, and so you win on the “short” calls (i.e. those that terminate before the 30sec mark), but lose on the “long” calls (i.e. those that terminate close to the 59 sec mark).
I wonder if there are any other catches?  Like, what happens after the 24 month period?  Does it revert back to the VodaGo per minute billing? – Probably not, so this is a way of getting people onto a “contract” and on to per second billing?
What happens if this offer’s minutes (R49 in the Vodacom case) run out during the month, can you topup by buying airtime at your currently used outlets?  {See here for an HTT article on where to buy your airtime: http://handytechtips.blogspot.com/2009/02/buying-airtime-can-be-done-in-numerous.html}

Here are more details:

 

Vodacom TopUp49 for R400.00 once off giving:                  R49 airtime per month for 24 months – a total of R1,176 Airtime                  Total Saving of 66%                  FREE SIM connection                  FREE CLI activation                  Calls billed per second

 

MTN TopUp100 for R800.00 once off giving:                  R100 airtime per month for 24 months – a total of R2,400 Airtime                  25 SMSs per month for 24 months – a total of 600 SMSs                  43.5 minutes talktime per month for 24 months a total of 1,044 minutes of talktime                  A total saving versus prepaid of R2,854 or 83%

 

Cell C ControlChat 100 for R800.00 once off giving:                  R115 airtime per month for 24 months – a total of R2,760 Airtime                  100 SMSs per month                  FREE SIM connection                  FREE CLI activation                  Calls billed per second                  Friends and family discounts to 7 numbers

Download the application forms here: http://www.mobile2mobile.co.za/downloads  {make sure that you have the latest Adobe Reader else you will get an error “There was an error opening this document. The file is damaged and could not be repaired.”}

Update on Wed23Sept2009:  Feedback from mobile2mobile CEO Warwick Ward-Cox answering some of the questions that I posed above:
”
From: Warwick Ward-Cox
Sent: 23 September 2009 09:04
To: HandyTechTipper@gmail.com

Morning HTT,

You are correct it’s an awesome deal,  I've personally taken out 3 now for the family.  This has to be the cheapest way to get airtime,  and with the networks now reducing call costs these deals will in the future be even more attractive if not already  ;)

The catch,  well you don't get a "free phone".  At the end of the 24 months, you have the option to carry on and pay an additional amount and carry on with the contract, or you will be downgraded to prepaid at the end of the 24 months.

Oh yes, and we don't do any network activation, until your deposit reflects in the bank account and has been cleared,  so depending on where you EFT from it can take about 3 days or so to be activated.  If it’s a cheque deposit then minimum 8 days until the cheque has cleared.  

Regards

Warwick Ward-Cox

Mobile 2 Mobile
http://www.mobile2mobile.co.za
”

International calling from your South African PrePaid cell phone: if you’re with Vodacom, then you’re getting ripped off!

If you have a Vodacom PrePaid cell phone, then here are some tips to avoid the very high Vodacom call charges (R10 per minute).  One could use an MTN SIM card and save over R6.51 per minute!  Or dial a local CellC number and save over R6.40 per minute – here’s how:

A friend asked me how much it was to call Italy from his MTN Prepaid cell phone – here are the outcomes from my investigations:
Vodacom PrePaid cell phone to Italy from a PayAsYouGo phone is R10 per minute. http://www.vodacom.co.za/pkgcr.do?action=getpkgmenus&pkgTypeId=2&pageId=21

{If you had a contract: Vodacom Talk120: International Calls (Per minute):
Off Peak: 0.99 + Telkom Off-peak (landline = 0.83; mobile = 2.82) ===> Off peak to a landline: R1.82 per minute; Off peak to a mobile: R3.81 per minute.
Peak: 2.10 + Telkom Peak (landline = 0.99; mobile = 3.19) ===> Peak to a landline: R3.09 per minute; Peak to a mobile: R5.29 per minute.
http://www.telkom.co.za/products_services/internationalcallservice/cost.html
}

 

For MTN PrePaid Classic: it costs (per minute) R3.49 to dial a mobile phone directly in Italy, and R2.90 to a landline in Italy (billed on a per second basis).
http://www.mtn.co.za/Travel/International%20Calling/Pages/default.aspx?index=2 

Wow, seems like MTN is MUCH cheaper than Vodacom…. But still, VoipBuster to Italy landline is free for 120 days!  See here for more details: http://handytechtips.blogspot.com/2009/08/voipbuster-over-skypeout-verdict-read.html

You could also dial this CellC number (084 198 0001) and speak to over 60 international countries for no extra cost: http://handytechtips.blogspot.com/2008/10/make-cellc-call-and-speak-to-over-60.html . This works for landlines only in Italy.
{Works for cell phones in these countries: USA (most networks); Canada; China; Singapore; Hong Kong.}

Costs of calls to CellC:
For Vodacom pre-paid Vodago to CellC: to Value-Added Services Off-Peak: R1.08; Peak: R3.60 http://www.vodacom.co.za/pkgcr.do?action=getpkgsgroups&pkgTypeId=2&pkgGroupId=8&packageId=17

For Vodacom contract Talk 240 to CellC: Value-Added Services Off-Peak: R0.98; Peak: R1.88 http://www.vodacom.co.za/pkgcr.do?action=getpkgsgroups&pkgTypeId=1&pkgGroupId=1&packageId=4

For MTN PayG Classic to CellC: Peak: R2.85; Off peak: R1.60 per minute.

See here for details of MTN’s peak and off peak calling times: http://www.mtn.co.za/Support/faq/NewSubscribers/Pages/MakingTakingcalls.aspx

So, HTT’s verdict:  since my friend was already with MTN (whew), his cheapest option to call a landline in Italy @off peak times is to dial the local CellC number which would cost R1.60 per minute. 
At peak times he should rather dial direct (ie: MTN call) @R2.90 per minute (the CellC number’s cost is R2.85 but the call setup time (while you’re keying in the international number on the CellC call) will use up time and nullify the 5c per minute savings).
If he needed to call a cell phone in Italy (the CellC number doesn’t cover cell phones in Italy yet) then he would need to dial directly @R3.49 per minute.

HTT’s verdict for other Vodacom PrePaid users: rather than paying the R10 per minute, get an MTN SIM card for your international calls.

But, for all of you that read this far… these costs can be slashed further if you use VOIP – even on your cell phone.  Install NimBuzz and configure a SIP connection using your VoipBuster account.  Then for the 1st 120 days you’ll pay nothing for landline calls to major international cities except for the data costs (R2 per MB on prepaid if you don’t have a data bundle). See here for more info:  VoipBuster over SkypeOut: the verdict? Read this for hands on tips on saving on your phone bill

Comply with the new law (RICA) and register your cellphone number today

RICA is the Regulation of Interception of Communications Act (and Provision of Communication-Related Information Act) and it requires that everyone who has an active cellphone number or purchases a new Prepaid Starter Pack, has to register their SIM cards from 1 July 2009.

Who must register?:
All current and new Contract, Top Up and Prepaid customers must register their SIM cards.

Existing customers:
Current subscribers who have activated their cellphone numbers prior to 1st July 2009, need to register their personal details against that cellphone number (SIM card) in order to comply with the RICA Act. This must be done within 18 months from the 1st of July 2009.

New customers:
When purchasing a new starter pack customers are required to register the new SIM card and provide their personal details. New SIM cards will only be activated on the network, once the relevant SIM card has been registered.

What information and documents do you need to take with you to register?
You are required to provide the following information when registering your SIM card:

• Cellphone number
• Full names and surname
• ID number or passport number - you will need to show one of the following documents as proof of identity: Green barcoded ID document or Temporary ID certificate, or Passport
• Your residential address: You will need to show any document that includes your name and residential address such as a bank statement, municipal rates, cellphone or retail account (not older than three (3) months), existing lease, rental or credit agreement, insurance policy, current TV or motor vehicle license.

If you live in an informal settlement you can provide a letter and/or affidavit from a school, church or retail store where you receive your post (this letter must be on an official letterhead or have the stamp of the school, church or retail store).

Please note: Registration must be done in person to confirm your identity.

Which SIM cards must be registered?
All Contract, Top Up and Prepaid cellphone numbers must be registered.
This includes:

• All data SIM cards used in smartphones, data cards, laptops, modems, etc.;
• Telemetry SIM cards such as the SIM cards used in tracking devices;
• SIM cards in lease-cost routers and other PABX routers;
• New SIM cards in order to have your cellphone number activated;
• Existing cellphone numbers - to ensure that your number does not get disconnected.

When is it your responsibility to be RICA compliant?

• If you own a SIM card
• If you are paying a cellphone contract for yourself
• When a family member's cellphone bill is in your name
• If you're a parent or guardian of minors using SIM cards
• When you transfer a SIM card from another individual's name into your name (Contract and Prepaid)
• When you port your cellphone number to another network.

The good news ;) Registration is free.


See here for more details: http://www.vodacom.co.za/Temp/vodacom9.jsp

Now, how does that affect all the visitors coming for the World Cup 2010 soccer tournament - HTT's tips need to be updated then?: Are you coming to the FIFA World Cup 2010?: How to get connected while you are in South Africa

Buying airtime can be done in numerous ways - HandyTechTipper weighs up convenience with discounts

I was looking for a online site that offered discounted airtime for my prepaid cell phone.
I previously used Discovery Vitality's Airtime that offered 10% discount (now discontinued and handed over to GotPrepaid).
I now purchase from Pick 'n Pay stores or Clicks.

I was looking for an online alternative - and here are my findings...

Buying airtime for your pre-paid cell phone is easy - go to any shop and they'll gladly sell you the airtime 'virtual' voucher that you can enter into your phone.
Online purchasing of airtime is also easy - if you have a credit card

HandyTechTipper (HTT) did a search for airtime vendors

Discounted airtime is also a bonus for the end user i.e. buy R29 worth of airtime for R27.

HandyTechTipper's ideal place to purchase airtime would be one that offered all of the following:
i) online vendor; ii) accept credit cards; iii) offered discounted airtime; iv) automated airtime credits.

Click here to download: BuyingAirtimeCalculatorFeb2009.xls

Note: not all vendors have been verified - use at your own risk!

Using the spreadsheet:

In worksheet "AirTimeOutlets":
Use worksheet "AirTimeOutlets" to see a summarised view of what's out there
Look through the offers and use the "ShortList" column to filter the offer that you are interested in and so home in on the offer best suited to your needs

In worksheet "DiscountedAirtime":
Use worksheet "DiscountedAirtime" to see what %age discounts are given.
Look through the offers and use the "ShortList" column to filter the offer that you are interested in and so home in on the offer best suited to your needs.

It seems that the following services come up tops for me:

http://www.airtimeforfree.co.za/ due to the highest discount and 26th voucher free offer [buy 25 of R12 vouchers for R287.50 and get airtime to the value of R312.00 [= 7.85% discount]].

http://www.vtime.co.za/ due to the random discounts and specials offered eg: R1,100 for R1,000
 
Pick 'n Pay and Clicks give small discounts (or ClubPoints), allow credit card purchases - but don't sell airtime online :(

Banks like FNB, ABSA are very convenient (no registration forms), online, 24x7, and transfer airtime immediately.

eBucks: gr8 to use up those bucks for airtime too.

Watch out for those "services" that require registration fee and transactional fees.

So, either go through the pains of registering and paying using EFT (and wait for your topup) to get your discounted airtime,
OR purchase online via your bank for immediate topups (but no discounted airtime).

Update on 7th April 2009:
I would love to be able to verify all the vendors listed but I do not have such funds (and time) at my disposal – for a proper verification of all services I would need to purchase at least 30 vouchers from each vendor and then calculate what the overall costs and savings were. This would (sort-of) then take into account the varying/random discounts and come up with a better comparison. But, even then, random prizes (eg: free cell phones, etc.) could not be taken into account…. I’d say that was an extra bonus that the end user shouldn’t bank on.

I have also noticed that http://www.vtime.co.za/Tips.asp have an ongoing offer of R1,100 airtime for R1,000.

Updated on 14July2009:
MTN users can now buy prepaid on credit (directly from MTN).
See here for more details: ITweb article

Update on 7th September2009:
Another service that accepts credit cards online is: BigTimeAirtime
There's also a small discount of R1 or R2 on amounts over R100 or so.