Questions and Help With First Budget Build

I am new too gaming pc and i have some questions for all experts. I want to build a budget gaming pc around 5OO no more then 55O. I live in USA and if you can help me with a build i would be grateful. Now i have some questions about parts.

When me building a budget i  thought about amd apu 58OOK with 8 gb of 1866 memory. and i would add a amd 667O in crossfire. I would like to know if this is a good idea for a budget build and if it would attomaticaly run crossfire with the gpu. And if the memory speed should be decreased or increased. 

Those were my questions. So thanks guys for helping out for a noob. If you wish to edit,create, or suggest a build then I will be grateful. Please keep it at 5OO or under if you HAVE to go over then dont do it by alot please. Thanks and srry for grammer I am doing this on my phone. 

In B4 raging lunatic who creams over APU's.

Also i forgot to add. I wish to be able to play BF3,Guild wars 2, Minecraft, World of Tanks above 25 fps on Medium to high graphics but no xAA. I do not need to play with ultra wiked graphics cus i am used to crappy x box graphics and that is why I am moving to Pc. But i am not selling the xbox. Just cause all my friends play live on it.