Buying a motor - Car, Van or Bike Make sure you do your homework and check price guides and compare similar cars in the classifieds etc so you know as much as you need about the value of different makes of cars, vans or bikes to avoid being overcharged ..... Try and find out who the seller is! Research the seller as much as possible. If you're buying a car, van or bike from a dealer, you can make sure they are registered traders etc.