Things Not to Say When Buying a Car:“I’m trying to keep my monthly payments down.”“Honey, what do you think?”,“I have a car to trade in; how does that affect the deal?”,“Here’s how much I have to spend.”These are some of the common mistakes people make when they enter a showroom. Avoid tipping your hand right when you walk in the door. You have no idea how much the salesperson is willing to deal, but if you blurt out your target price, you can be sure that he’s not going to offer you anything lower than that.