Buy.com has the refurbished HP Pavilion Elite m9500f Desktop for $500 with free shipping. Includes keyboard and mouse. PC specs below. [Compare]

750GB SATA 3G HDD, Phenom-9750 2.4 GHz, 8GB DDR2

GeForce 9500 GS, 802.11 a/b/g/n, Vista Home Premium x64

SuperMulti DVD+/R Drive, Wireless-N, 15-in-1 memory card reader