A car sales man once made the following pitch to one of your authors: ''If you buy this $10,000 car with cash, you will lose at least $1,500 over the next 3 years in forgone interest (assumed to be 5 percent per year). If you take one of our low-cost auto loans, you only have to pay $315 per month for the next 3 years. That amounts to $11,340-$10,000 for the car and $1,340 in interest. With our car loan, you will actually save $160 in interest.'' What do you make of this argument?