Have had the Prius 10 months now. I drive approx 20K / year. About 2 months after driving the car, I started paying myself 10cents / mile, which was about the savings over what I was paying for gas for the 15MPG Jeep and what I pay for gas now with the prius. Been tossing the money into a little box next to the desk, just counted it and it's over $1500 now (I have close to 18K miles on the car). I try to hold a car for 10 years, so I'm thinking that at this rate, I might be looking at a sizable chunk of dough, close to a "free car" in 2015. Hope the prius holds up for 9 more years without substantial mechanical failure and costs.....
If you put it into an interest bearing account or other investment instrument, other than the 'little box next to the desk', and not including 'under the mattress' you'll be much further down the road to a new car in 10 years. At a minimum you should experience the 'miracle of compound interest'.
