Buy a new or used car these days and you can expect the salesperson to pressure you to buy a service contract or "extended warranty." For a fee, which is usually rolled into the financing, these products provide repairs or maintenance for a certain period of time, say 2 years or 24,000 miles. But they rarely provide much benefit to the buyer and often only serve to pad the dealer's bottom line.

Here's an example of what I mean. In a recent case, our client bought a used vehicle with over 100,000 miles on it. The client also bought a service contract for an additional $2,500 or so. The service contract lasted for 5 years or an additional 100,000 miles. Our client rolled the cost of the service contract into his loan for about $50 a month. At this point, you might be thinking this sounds like a pretty good deal.

However, the fine print of the service contract provided for a maximum reimbursement of only $3,000, less a $100 deductible. So the maximum reimbursement was actually $2,900. Further, a great deal of possible mechanical problems were excluded from coverage.

 So, our client paid $2,500 for the right to be reimbursed $2,900. In other words, he paid $2,500 to potentially receive an additional $400, but only if: (a) a problem occurred; (b) the problem occurred during the term of the service contact and (c) the problem wasn't excluded from coverage. He would have been better of declining the service contract and putting the $50 a month into a savings account. The savings account could have been used for any repair at any time. And if no repairs are necessary, he could have used the money for something else.

Before agreeing to buy any service contract, make sure you understand the total cost (not just the monthly cost), the total amount of coverage, and what is covered and what's not. Don't rely on the salesperson to tell you these things, read the terms for yourself. And if you don't understand the terms, it probably doesn't make sense to buy it.