The us of crypto currencies like buying and selling and transacting with it are legal in the countries of Southern Africa. If you want to know where I found this read here - https://en.wikipedia.org/wiki/Legality_of_bitcoin_by_country_or_territory#Southern_Africa

So I dont see any reason not to do so. If you are looking for people to trade with then you cloud visit LocalEthereum a newly launched Ethereum P2P exchange or sign up on an exchange that allows deposits in your local currency. Then use your money to buy whatever coin you wish to. I hope that helps, if you have any other related question feel free to ask.