Depending on the make and model, dealers typically allow you to charge anywhere from $1k-$5 for a new car. Don't know for used, because I never bought a used car.
My car is in perfect condition and has been well serviced over the years, but every time it goes in the shop, it takes a few days, because they CAN'T get parts cause the car is 12 years old. So, I gotta get a new car, creates too many problems for me when I don't have an operating vehicle.
it's kinda of funny that you used "my car is in perfect condition" and "can't get parts" in the same sentence. It was amusing. Anyway, mind if I ask what kind of car it is? As a hobby I'm sort of a car junkie?