CompUSA.com offers the factory-refurbished Gateway AMD Phenom 2.2GHz Quad-Core Desktop PC, model no. DX4710-UB001A, for $549.99. With $1.99 for shipping, that's the lowest total price we could find. Features include an AMD Phenom 9550 2.2GHz quad-core processor, 6GB RAM, 640GB hard drive, dual layer DVD burner with LabelFlash, 15-in-1 memory card reader, and Windows Vista Home Premium 64-bit. A 90-day Gateway warranty applies.