I wouldn't go much lower in specs than this. Otherwise you wont be gaming much.
PCPartPicker part list:
https://pcpartpicker.com/list/dNm6sZ
Price breakdown by merchant: https://pcpartpicker.com/list/dNm6sZ/by_merchant/
CPU: AMD - Ryzen 3 2200G 3.5GHz Quad-Core Processor ($99.69 @ OutletPC)
Motherboard: ASRock - A320M Micro ATX AM4 Motherboard ($32.99 @ Newegg)
Memory: G.Skill - Aegis 8GB (2 x 4GB) DDR4-2400 Memory ($87.99 @ Newegg)
Storage: Western Digital - RE4 1TB 3.5" 7200RPM Internal Hard Drive ($42.50 @ Amazon)
Case: Raidmax - Viper II ATX Mid Tower Case ($50.71 @ Newegg)
Power Supply: Corsair - VS 500W 80+ Certified ATX Power Supply ($79.89 @ OutletPC)
Total: $393.77
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-04-07 01:46 EDT-0400