In that price range your lookin at high miles, ~150,000.
Most likely whoever has or had the car drove it hard and with alot of miles it really needs to be checked over thoroughly. If you find one at or below 120,000miles I think you would make out for 5k, assuming the interior isn't thrashed and paint is okay. the longer you wait the better your odds.
1998 Bright Atlantic Cobra - 3:73's, BBK ls, Pro 5.0, 96 Cobra STB, Borla XR-1 Catback, Custom Catch Can, Spec clutch, MM Firewall adj, FRPP wires, RSD, Spoiler delete, 245/275 BF Goodrich g sports on chrome 95 cobra r's
1998 V6 Mustang : SOLD!