To put it bluntly, you go to the garage to sell your old car to them, and then use the money from selling the old car as the car money for buying a new car from their home. More refunds and less subsidies. Car dealers have various trade-in policies. In short, the principle of trade-in is that your old car should be sold at the highest price, your new car should be bought at the lowest price, and the gifts are the most. If it is mortgaged, it depends on their loan policy. It should be noted that there are both interest-free loans and discount loans. Wool comes from sheep, and no car dealer will do business at a loss, and the loan bank will not make unprofitable sales. It should also be noted that the GPS necessary for the loan car can be added or not. If you don't add it, you can buy a car for theft and rescue. In short, this is to save more money when buying a car!