Crazy impressive stuff.
I did a rough spec of his PC:
CPU: AMD - Ryzen 7 1700 3.0GHz 8-Core Processor ($284.99 @ Amazon)
Motherboard: Asus - STRIX B350-F GAMING ATX AM4 Motherboard ($102.89 @ OutletPC)
Memory: Corsair - Vengeance LPX 16GB (2 x 8GB) DDR4-3000 Memory ($191.99 @ Newegg Marketplace)
Storage: Western Digital - Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($43.78 @ OutletPC)
Video Card: XFX - Radeon RX VEGA 64 8GB Video Card ($524.98 @ Newegg)
Case: NZXT - S340 (Black) ATX Mid Tower Case ($63.99 @ SuperBiiz)
Power Supply: EVGA - SuperNOVA G2 650W 80+ Gold Certified Fully-Modular ATX Power Supply ($99.89 @ OutletPC)
Operating System: Microsoft - Windows 10 Home OEM 64-bit ($88.89 @ OutletPC)
Total: $1401.40
Pretty fucking awesome, a $500 box keeping parity with a $1400 PC!