RefurbforLess via eBay offers the refurbished HP Pavilion AMD A8 2.2GHz Desktop PC, model no. 550-A122, for $219.99 with free shipping. That's $280 off and the lowest total price we could find. (It's also $180 under the best deal we could find for a similar new HP desktop elsewhere.) It features an AMD A8-7410 2.2GHz quad-core processor, 8GB RAM, 1TB 7200 rpm hard drive, DVD burner, 802.11n wireless, Bluetooth, media card reader, DVI, and Windows 10 Home 64-bit.
A 90-day warranty applies, although it's not clear who backs it.