So - $600US no monitor, ram or OS? What ram, monitor and OS do you have? - So they will be compatible.
Meanwhile, try -
CPU: AMD FX-8370 4.0GHz 8-Core Processor ($169.99 @ Amazon)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler ($29.98 @ OutletPC)
Motherboard: Asus M5A99FX PRO R2.0 ATX AM3+ Motherboard ($118.98 @ SuperBiiz)
Video Card: Gigabyte Radeon R9 270X 2GB WINDFORCE Video Card ($164.99 @ Newegg)
Case: Corsair 300R ATX Mid Tower Case ($59.99 @ Micro Center)
Power Supply: XFX 550W 80+ Bronze Certified ATX Power Supply ($44.99 @ NCIX US)
Optical Drive: LG GH24NS95 DVD/CD Writer ($19.96 @ OutletPC)
Total: $608.88