You can start with this
PCPartPicker part list:
http://pcpartpicker.com/p/JNhL8d
Price breakdown by merchant: http://pcpartpicker.com/p/JNhL8d/by_merchant/
CPU: AMD Athlon X4 860K 3.7GHz Quad-Core Processor ($67.99 @ NCIX US)
Motherboard: Gigabyte GA-F2A78M-D3H Micro ATX FM2+ Motherboard ($48.49 @ SuperBiiz)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1866 Memory ($29.99 @ Newegg)
Storage: A-Data Premier SP550 120GB 2.5" Solid State Drive ($41.99 @ NCIX US)
Video Card: Asus GeForce GTX 750 Ti 2GB Video Card ($106.99 @ SuperBiiz)
Case: Fractal Design Core 2500 ATX Mid Tower Case ($43.99 @ NCIX US)
Power Supply: Antec EarthWatts Green 380W 80+ Bronze Certified ATX Power Supply ($42.99 @ SuperBiiz)
Optical Drive: Lite-On iHAS124-14 DVD/CD Writer ($12.99 @ Newegg)
Operating System: Microsoft Windows 10 Home OEM (64-bit) ($89.88 @ OutletPC)
Total: $485.30
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-12-16 20:44 EST-0500