There are plenty available. Where are you based? If in Pretoria, then there are a few variants at New World in Menlyn, at various prices. Some have the ability to read straight off of a USB Flash disk, others don't. Some can read SD cards, others can't etc. Most of them have a 2.5mm or 3.5mm input so that you can plug your iPod, phone, etc in. Some even have remote control.
Expect to pay between R120-00 and R400-00, depending on your needs.