Here is one that is just under $300 for basic budget gaming
PCPartPicker part list:
https://pcpartpicker.com/list/ZVMxFt
Price breakdown by merchant: https://pcpartpicker.com/list/ZVMxFt/by_merchant/
CPU: AMD - Ryzen 3 2200G 3.5GHz Quad-Core Processor ($99.88 @ OutletPC)
Motherboard: MSI - B350 TOMAHAWK ATX AM4 Motherboard ($64.99 @ Newegg)
Memory: G.Skill - Ripjaws 4 Series 8GB (2 x 4GB) DDR4-3200 Memory ($102.99 @ Newegg)
Total: $267.86
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-03-14 16:36 EDT-0400
Here is one for +40 over budget that will be a good bit better at gaming:
PCPartPicker part list:
https://pcpartpicker.com/list/z4JrxG
Price breakdown by merchant: https://pcpartpicker.com/list/z4JrxG/by_merchant/
CPU: Intel - Pentium G4560 3.5GHz Dual-Core Processor ($58.79 @ OutletPC)
Motherboard: MSI - B250M PRO-VD Micro ATX LGA1151 Motherboard ($49.90 @ OutletPC)
Memory: GeIL - EVO POTENZA 8GB (2 x 4GB) DDR4-2133 Memory ($78.99 @ Newegg)
Video Card: Gigabyte - GeForce GTX 1050 2GB OC Video Card ($154.99 @ Amazon)
Total: $342.67
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-03-14 16:38 EDT-0400