Read the Small Print

When it is time to sign your contract for that new car, make sure you are signing a completed contract and every detail is approved and correct. Don’t let people run your credit report unless you are sure you’re going to be financing with them. Each time your credit report viewed, your credit score will decrease. Some dealerships claim it’s their policy, even for those who are paying cash for a car. Don’t let them.
They will still make that sales deal without it. Double check their figures to make sure your down payment, trade-in, and rebates are being directly applied to the sale price of the car you are buying and that they are correct. According to ‘Lectric Law Library: Auto Dealer “Swallowing” Of Customer Down payments, Trade-Ins and Rebates, there have been many instances of these dollars disappearing (usually into dealers pockets).
Additional Dealer Markup charges can include rust proofing, undercoating, VIN etching, as well as dealer prep and other fees. Always question these costs if they’re included in the deal. None of these add-ons are written in stone, even though the dealer may want you to think so. Watch for the “subject to financing” statement.