I'd opt for this as that motherboard won't support that 8 core FX without very good VRM cooling.
PCPartPicker part list:
http://pcpartpicker.com/p/GZ3vwPPrice breakdown by merchant:
http://pcpartpicker.com/p/GZ3vwP/by_merchant/CPU: AMD FX-6300 3.5GHz 6-Core Processor ($93.99 @ Amazon)
Motherboard: Gigabyte GA-990FXA-UD3 R5 ATX AM3+ Motherboard ($82.98 @ Newegg)
Storage: A-Data Premier SP550 120GB 2.5" Solid State Drive ($34.99 @ Newegg)
Video Card: Gigabyte Radeon R9 390 8GB Video Card ($299.99 @ SuperBiiz)
Total: $511.95
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-04-26 07:44 EDT-0400
It will work fine, if he sees VRM temperature spikes he can purchase a bag of VRM heatsinks for $3.
I'd do exactly as Rapture recommended.