I've been messing around with putting parts together, unfortunately prices are in UK Pounds but I managed to 'build' a decent PC. Without a graphics card it was just under 380 pounds, but I'm sure a 100 pound+ graphics card would make a fully functional gaming PC.
CPU/APU: AMD Ryzen 3 2200g
Motherboard: Asrock AMD Pro4
RAM: 8GB
Storage: 1TB Hard drive + 128 M.2 SSD
PSU: Ace BR Black 700W
Case: Antec VSK 3000B