The process for trading in a car typically involves visiting a dealership or car buying service and getting an appraisal of your vehicle. The appraiser will evaluate the condition of the car, its mileage, and other factors to determine its value. If you decide to trade in the car, the dealer will offer you a trade-in value that can be applied to the purchase of a new or used car. You can negotiate the trade-in value to some extent, but keep in mind that dealers need to make a profit on the sale of the car.