percussion muzzle-loading pistol bought at a gun show a few years back for $45
Doh! You just reminded me that I have one of those. Okay, so that's my cheapest handgun. It was a kit, given to me by a brother who had received it as a gift and let it rust. It wasn't pre-blued. I had to blue it after getting the rust off with steel wool. The wood grips were big blocks that I had to cut and sand to fit me. I had to "season" the cylinder in the oven in cooking oil at 350 degf. I had to buy .44 lead balls, and #11 caps and fffg powder and learn how to load and shoot a reproduction of a Colt Army Model 1860 revolver. I guess if my time was worth anything, it was probably my most expensive handgun.