Apple have sent out an email to developers with information about price changes in a number of countries. On that list South Africa is mentioned as getting a price increase on the App Store, iTunes Store, iBook Store due to the current exchange rate.
Many people have been enjoying the very low price on music in South Africa with many people who had US iTunes Accounts moving to South Africa accounts to get the better price. However that may all change with these price increases.
We are not sure what the increase will be like but they will start taking effect in the next 24 hours. Due to the fairly large increase in the exchange rate we are electing the prices to change significantly.