I did this 20 years ago with my first and only NEW car. First real job, bought a new car, woo hoo - 1995 Honda. Monthly payment. Drove it for 6 months, making my payments, HATED the payments- took it to the dealer and traded it in. Got another Honda, fully paid off, with about 100K miles on it. Was not on super savings journey then , just learned that I hated having a monthly payment.
Have had 5 cars since, one of which I still have. 2000 Toyota Echo, bought with 67k miles on it in 2005, ( for around $6500) currently has 125K miles on it (2015). 2 of those other cars were for SO, we only have one car now. One we had for 10 years, also bought at about 5 yrs old with 60-70,000 miles, put another 100,000 on it.
I lost a few grand on the new car to old car trade, but I saved 40 months of payments and untold money on insurance. When you buy a car outright and have a small cushion ( over 4k) you don't get the collision insurance, you just get liability. Drive safely and all you need is liability. 2 of those cars I no longer have were "totaled" ( rear ended in stop and go traffic). Bends the frame that holds the bumper, makes the bumper, smooshe in. The driver's insurance who hit you
gives you a $2000 payment and you keep driving your "totaled car".
Sell the new car. Buy a used car outright. Drive it for 10 years. Repeat.