My dad recently tried privately selling his 2005 GT Mustang, and got no response at all. It is very well kept, and has almost no miles on it... I'm not sure exactly what he was asking, but I think I heard him say 19. I think he puts some of the blame on gas prices. Thought you might want to know.
According to Edmunds... based on what I remember about his car he should have been about to get $22,6. The national base trade in is $19,033.