8ta / Telkom Mobile
Good network

I am a prepaid customer for about a year now, very happy with the service. Never had a dropped call, data service is super fast on 3G. Cheap call and data rates. Fair coverage, but excellent in urban areas.
AND FREE STUFF GIVEAWAYS! Got 2 Gig of data free in December. What more do you want from a supplier!
Exellent!!!