A full warranty applies to anyone who owns the vehicle during a specified period. The dealer agrees to make the repair with no parts or labor charges, and to give a refund or replacement if a problem can't be fixed. The charge levied for a repair often is high enough so half the total is enough for the dealer to break even. Your half may well be all profit. Some warranties are only good for one week.
Every warranty has limitations.
Find out exactly which components and systems are covered, for how long, and for how many miles. If the dealer agrees to make any repairs beyond those stated on the sticker, get his agreement in writing on the contract. Implied warranties are usually good only for a limited period. Though the dealer makes no promises to repair the car, an implied warranty gives the buyer some legal leverage to get the seller to correct flaws that weren't evident when the vehicle was sold. Implied warranties vary by state, and may exist even if no written warranty is supplied.