Another option is to go to your banking institution and ask them how much they will loan you to purchase a car. After telling the dealership you absolutely won'

Another option is to go to your banking institution and ask them how much they will loan you to purchase a car. After telling the dealership you absolutely won't use whatever financing they are offering, have them write up a cost sheet of the vehicle you're interested in and tell them you will show this to your bank. This will usually do one of two things: the dealership now knows you have a bank behind you who is looking out for your interests. (If they're not, change banks!) And it gives you an opportunity to get a possible better interest rate from your bank, who will surely want your business. The cost sheet also makes then spell out exactly what the cost and the extras are on the vehicle.