I once had a dealer beg me to fiance a new car even though I had the cash. Promised no early payment penalty in the loan.
So I had them draw up the papers, buy me a coke and let me sit down and read them Sure enough, while no early payment penalty, I still had to pay ALL the interest. Very careful wording to hide that, took me over 1/2 hour to find it.
I got out my check book. wrote out a check for the amount we had agreed, said take it or leave it. I had a friend that worked there, they knew that. He said the sales manager came up to him with a check, and asked if I could do that. Mike smiled and said oh yea. The sales manager said why do we not know him. Mike said he is frugal, well he probably said tight ass but you get the picture.. He told them they were lucky I was there at all.
They ended up taking the check. Last new car I ever bought. It was a lemon.