Trade in program for old rig?

I have been looking at Peterbilt and Kenworths on Truckpaper for a long time. To find one in good shape it is usually around $40,000. Occasionally I find one cheaper and I wonder what's wrong with it. Many of them have fresh paint for a cheaper price and is obviously covered in rust and not worth a plugged nickel. Everyone likes to spray paint the rear frame to make it look nice. Some actually have the air bags spray painted. First pressure wash job will have you realizing how badly you messed up. My point is, a mint condition truck like that is worth every bit of $40,000 and OP could sell it no problem.