What should I read before signing car paperwork?

Read the purchase agreement or buyer's order, retail installment contract or lease, and any add-on or warranty forms. Confirm the VIN, price, trade-in value, payoff, down payment, APR, loan term, monthly payment, and total amount financed match what you agreed to. Make sure there are no blank spaces and that optional products you declined aren't included. Ask about anything you don't understand, and get copies of every signed document before you leave.