Newegg offers the refurbished HP Debranded Intel Haswell Core i5 2.9GHz Desktop PC, model no. TS-C971-007-W8PRO, for $379.99 with free shipping. That's $170 off list and the lowest total price we could find. It features an Intel Core i5-4570T 2.9GHz Haswell dual-core processor, 4GB RAM, 1TB hard drive, DVD burner, and Windows 8 Pro.
A 90-day warranty applies, but it is unclear who backs it.