Not a car, but bought a 1949 Matchless motorcycle off Craigslist for a good price. It had been in the I’m older now but still running against the wind Bob Seger 60th anniversary 1961-2021 shirt garage for 15 years. He’d never been able to start it. I found that it was a positive-ground system and he had connected the battery cables backward. Started right up and ran fine. While in prison, he takes up the advice of a jailhouse “lawyer” and repudiates the original plea deal. The heavens open and he is to be re-sentenced for up to 50 years. Justice hasn’t yet been served, but at least it now has a plate, knife and fork.