If you want to build "close to target", you could start with my "PS4 Pro" build and adjust as necessary:
PCPartPicker part list: https://pcpartpicker.com/list/g9L6pb
Price breakdown by merchant: https://pcpartpicker.com/list/g9L6pb/by_merchant/
CPU: AMD Athlon X4 880K 4.0GHz Quad-Core Processor ($89.99 @ NCIX US)
Motherboard: ASRock FM2A68M-DG3+ Micro ATX FM2+ Motherboard ($44.99 @ SuperBiiz)
Memory: Crucial 4GB (1 x 4GB) DDR3-1600 Memory ($24.88 @ OutletPC)
Storage: Toshiba 1TB 2.5" 5400RPM Internal Hard Drive ($53.50 @ Jet)
Video Card: Gigabyte Radeon RX 480 4GB G1 Gaming Video Card ($204.98 @ Newegg)
Case: Rosewill RANGER-M MicroATX Mini Tower Case ($34.99 @ Newegg)
Power Supply: SeaSonic S12II 430W 80+ Bronze Certified ATX Power Supply ($46.98 @ Newegg)
Optical Drive: LG WH14NS40 Blu-Ray/DVD/CD Writer ($46.88 @ OutletPC)
Total: $547.19
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-01-18 13:00 EST-0500
The only hold up is I'm not sure how the system profile would work, like if it's run on target or off target. But that's probably only if you really care about etching out high performance code.
Note about RAM: The consoles divvy up RAM in a manner that roughly half is used for graphics and half is used for applications. And it's up in the air, but 2-3GB of that application RAM is used for the OS and its functions. So 4GB here would be closer to target than 8GB.