PCPartPicker part list:
http://pcpartpicker.com/p/3idxA
Price breakdown by merchant: http://pcpartpicker.com/p/3idxA/by_merchant/
Benchmarks: http://pcpartpicker.com/p/3idxA/benchmarks/
CPU: AMD Athlon X4 750K 3.4GHz Quad-Core Processor ($79.98 @ OutletPC)
Motherboard: Gigabyte GA-F2A75M-HD2 Micro ATX FM2+ Motherboard ($64.99 @ Newegg)
Memory: GeIL EVO POTENZA 8GB (2 x 4GB) DDR3-1600 Memory ($62.99 @ Newegg)
Storage: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($59.55 @ Amazon)
Video Card: EVGA GeForce GTX 750 Ti 2GB Video Card ($149.99 @ NCIX US)
Case: NZXT Source 210 (Black) ATX Mid Tower Case ($37.99 @ Micro Center)
Power Supply: Corsair Builder 430W 80+ Bronze Certified ATX Power Supply ($39.99 @ Amazon)
Total: $495.48
best you can do in the budget.