I traded in an old old explorer(that got between 12-16 to the gallon) for a new Kia that gets between 28-36. I would have bought the car outright but got 0% interest. And after the trade in my monthly payment is $273 a month. I save about 1000 gallons a year. With gas at about 2 now that's only 2000 a year but even last year has average about 2.25 though out the year. So about $2,250. I am not saying it's break even because it's not but I wanted a new car and the fact that it is only going to cost me between 800-1000 a year after the gas saving was definitely part of the calculation