You are negotiating on a car when the salesperson finally gives you the good price you've wanted. Sensing that you're very close to making a decision to buy, the salesperson might smile and say the magic words: "So, do we have a deal?"
Wait. Don't shake hands just yet. Instead, say your own magic words: "Your price sounds good, but first I need to know the out-the-door cost."
What you're really asking is: "Are there any hidden fees or extras in the contract?" As a buyer, it's better to learn about such fees at this point, before the deal is final, than when you are in the finance and insurance office about to sign the contract.