Gateway DX4860-UR31P Desktop PC for $499.99.  Shipping is $13.27 for a total of $513.26 shipped.  Here is a screenshot for your reference.  It features an Intel Core i5-2320 processor at 3.0GHz, 4GB DDR3 RAM, 500GB hard drive, 16x dual layer DVD burner, Gigabit Ethernet, multi-in-one media card reader, and Windows 7 Home Premium (64-bit)