This is the best I could do on your budget. The total comes to ~$465. Use the extra cash to pay tax or bump up the GPU.
You'll be able to play DX11 games at 1080 on medium settings while maintaining 60 FPS.
Motherboard: AM2+/AM3/AM3+ (~$70)
CPU: Athlon II X4 640 (~$75)
GPU: Radeon HD 7790 (~$120)
RAM: 8 GB (2x4 GB) DDR3 1600 (~$60)
SSD: SanDisk Ultra Plus 64 GB (~$70)
HDD: 1 TB Western Digital Blue or Seagate Barracuda (~$70)