Well...I had a '79 D150 with no motor. It was a rust-free truck, and straight save a replacement front fender. Not a bad rig. I listed it on CL for $300. Nothing. No Bites. Nada.
So I pulled it, waited a week, said "What the hell..." and listed it for $750. Same pics, same truck, same seller, same location, same phone number, same ad (price edit, natch), same everything. They fought like dogs for that truck.
I got calls for weeks after the the guy showed up SAME DAY (and paid ca$h with no bargaining) to get it.