Well, I assume you are going for a gaming rig. If you require a screen, mouse, speakers & keyboard, then save up around R1000 and grab yourself those items or get it somewhere cheap, you can always upgrade that easily later. Also, I'll assume your not going to overclock (you'll need a bigger budget for that), and if you want to go AMD, look at a AM3+ mobo and the FX6300 CPU.
Here is my specs for the budget gaming case:
CPU: G2120 - R885
http://www.rebeltech.co.za/index.php?main_page=product_info&cPath=11&products_id=7610
Great value budget CPU. Will need to upgrade it in the near future though.
RAM: GSkill Ares 1600mhz 8GB (kit) - R511
http://www.rebeltech.co.za/index.php?main_page=product_info&cPath=1&products_id=6331
Good value for money Gaming RAM. Don't need anything more, or less, and you don't have to upgrade this in the near future.
Mobo: MSI H77MA-G43 - R888
http://www.rebeltech.co.za/index.php?main_page=product_info&cPath=19&products_id=6561
Standard, good value for money, mobo. No overclocking though.
HDD: Seagate Barracuda 1TB (64MB cache) - R796
http://www.rebeltech.co.za/index.php?main_page=product_info&cPath=26&products_id=1255
GPU: PowerColor HD7850 (2GB) - R2099
http://www.wootware.co.za/powercolo...ci-express-3-0-x16-desktop-graphics-card.html
Wootware has all the Radeon 7000 series cards for INSANE prices!!! Don't have to look anywhere else for a GPU. I asked Rebeltech if they could stock it but they can't. This is by far the best budget card available in SA!! For everyone else reading this: HD7950 R3200.... AWESOME!!
Case + CPU: Ask at Rebeltech for the SuperChannel 711 Gaming case (includes 750 Watt PSU). -R795 (email for quote)
It's a bargain! I have one!

It comes standard with a 750 Watt PSU, 2x USB3.0, fan speed control, 1x 140mm blue LED side fan, 1x front 120mm blue LED fan, and 1x rear 120mm fan. It also has a tool-less setup and looks amazing!
http://www.superchannel.co.za/index.php?option=com_content&view=article&id=38
Total: R6080 <-- For all the above? I couldn't believe it when I was building on a budget...
Get the PowerColor HD 7770 - R1399 if you still need to budget for the Screen, Keyboard + Mouse, and Speakers.
http://www.wootware.co.za/powercolo...ci-express-3-0-x16-desktop-graphics-card.html
Your CPU will be the bottleneck. If you can save up R400 more get the i3-3220 CPU. It will get you a few more FPS in games.
http://www.rebeltech.co.za/index.php?main_page=product_info&cPath=11&products_id=7590
For the future: I'll recommend upgrading the CPU first, then the Mobo. Your RAM will be fine for the next 2 years until the DDR4 release (and availability + affordability). Your Graphics card will have you set for at least 2 years as well.
Hope it helps!