You've shopped around for months and you've finally found your new car--the perfect combination of stylish and affordable. The guy at the dealership is helpful and you're ready to move from the showroom into the office to make it official.

After preparing the contract for a few minutes, the salesman hands you the final invoice - which, it turns out, is a little more than you expected.

You ask about several of the charges ("underneath paint sealant", "seats' fabric spraying with protective silicon", "rust-proofing spraying", and "necessary new alarm") and he tells you it's a must purchase. Only a fool would buy a car without rust-proofing, and besides, the cars come to the dealership like that, he says. Before you know it, your car is almost a thousand dollars more than expected and your salesman is driving home from the dealership in his new car, courtesy of your commission.

How to avoid: adding certain things may seem like a necessary part of the sale, so many people just accept the charges and move on with their lives. You don't have to get at least some of them, and maybe all of them, so stand up for yourself and call their bluff!