<human>:  What should I know before buying a used car?
<bot>: Before buying a used car, you should know the car's history, such as service records, any accidents or damage it has had, and its market value. You should also take the car for a test drive to get a better idea of its condition. You should also have the car checked by a mechanic to ensure that it is in good working order. Additionally, check to see if the seller is offering a warranty or guarantee, to help protect you in the event of any issues with the car. Finally, research the car's resale value so you can make sure you are getting the best deal.