[basjoos]

I just convert their mileage and my mileage into cents per mile and compare how many miles a dollar takes them and me down the road (just like like throwing a dollar bill out of the window every "x" miles you drive down the road). Then I take a popular local destination, calculate how much it costs them in gas to drive there and how I could drive there, take the amount of money they paid for their gas to get there, use it to pay for my gas, and still have "X" dollars left over to buy a burger and fries.