There are a few things you should avoid saying when buying a car, as they can ultimately sabotage your negotiation efforts. Here are four things to keep in mind: 1. Don't say you're not interested in the car. If you've taken the time to come into the dealership and test drive a car, it's likely that you are at least somewhat interested in purchasing it. Telling the salesperson outright that you're not interested will only give them more room to lowball you on price. 2. Don't say you have a trade-in. If you plan on trading in your old car, don't mention it until after you've negotiated the price of the new car. The value of your trade-in will be used as a bargaining chip by the salesperson, so it's best to keep it out of the conversation until you've settled on a price for the new car. 3. Don't say you're not interested in financing. If you're planning to pay cash for the car, don't say so upfront. The salesperson may be more inclined to give you a better deal if they think they have a chance to make some money off of financing. 4. Don't say you're not in a hurry. Even if you're not actually in a hurry to buy a car, acting like you are can put some pressure on the salesperson to give you a better deal. They may be more likely to give you a discount if they think you're going to walk out the door and buy a car from another dealer.