I was selected as part of their beta team back in January when they were testing the sms service. It was free back then. Then when they launched it, initially they were free. But now, they probably charge. I disconnected it. Doesn't work well with ADSL it seems.
Well, i've probaly send about ~4000 SMS via Telkom since the beginning of the year, and i didn't pay. I have about ~5000 SMS on my cell INBOX, so it can be ever more.
It is still FREE Homesms service to another landline and to all cell providers. The catch ? you must but a sms-friendly phone (not necessarily from Telkom , but it must have the ICASA stamp of approval), with Calling Line Identification which costs R10 pm