While nobody was looking, the University of Johannesburg has created a bunch of 100% online degree programs. Move over UNISA, there's a new kid in town. https://www.itweb.co.za/content/O2rQGMApKRD7d1ea
The more the merrier, I suppose, although it hardly bodes well that after crowing about "innovative educational tools" the only thing they list is Blackboard.
So about 2000 USD for a masters degree if I have added it up right. 28440 R. Worth looking at if this is for Int. students also.
I'd think it's the same for everybody. As far as I know, SA Universities receive the same per-student Government funding for foreign or domestic distance students - so, six of one, half a dozen of the other. That's likely why they don't charge foreigners extra. Thank goodness for unusually generous Government policies and ... depreciated currency! If either factor changes, you can probably kiss one of the last bastions of excellent, really low-cost higher education goodbye.