A new car is a significant expense and one that you're likely stuck living with for a number of years. New cars offer the security of a factory warranty and the knowledge that no other driver has damaged or mistreated the vehicle. Once you sign the papers, the car is yours unless you fall into a situation that delays the sale from becoming official.

Documentation

The purchase contract that you sign when you buy a new car is a legally binding document. This means that you're required to comply with the terms listed, and so is the dealer. If the purchase contract doesn't state terms for a return policy, there is no such option. Once you sign the papers you own the car, and the dealer is under no obligation to return your money. This is why it's so important to understand what you're signing. If you don't understand a document, ask the dealer to explain it to you. If you still feel uncomfortable, ask someone you know with more legal knowledge or car-buying experience to come with you to the dealership and review the documents.

Return Policies

Some new car dealers offer limited return policies. These are optional policies that dealers offer for a specified period, such as three days or five days. Because dealers set their own return policies, they also set the terms. Drivers may be liable for a mileage fee for any use of the new car, or a restocking fee as a percentage of the car's value. When there is a valid return policy, the sale is final as soon as the return period elapses.

Loans

If you use an auto loan to buy a new car, the sale isn't final until you pay off the loan in full. While the papers that you sign complete the car dealer's role in the transaction, you also enter into a transaction with the new owner: the lender. As you make payments you build up equity and own a larger and larger portion of the car. However, the sale isn't complete until you make your final payment and receive the title from the lender. This means you can't sell or trade your car until the loan is paid off or you receive special permission from the lender.

Lemon Laws

Some states have lemon laws for new car buyers to protect drivers from dealers who sell vehicles with major mechanical problems. Lemon laws that apply to new cars typically cover them for a period of up to one year from the date of purchase. These laws require drivers to make multiple repair attempts and notify the dealership or automaker in writing before pursuing a lemon law refund. In cases where automakers refuse to honor their warranties and can't repair a vehicle, the state may be able to force the dealer to issue a refund or replacement vehicle. Once a driver owns a car beyond its lemon law protection period, the sale is irrevocable and the dealer is under no obligation to issue any refund.