There are a multitude of domain name registration services as listed by other student and you could also mention Paradigm solutions who lured me to their web page by quoting a monthly rate equivalent to an annual rate of R89 – not the cheapest.
If you want cheap, Plant.co.za will register a .za.net or .za.org for R80 – once off with no annual renewal fees.
Some of the dollar priced offerings may be cheaper.
Who gets the money? After fee registration costs, the ISP pockets the rest.