At least last year, "new car loans" had a really low rate, and I think as long as it's newer than 3 years old and less than 30k miles or something a used car still qualifies.. if you have money making more in interest than the loan percentage, you shouldn't pay cash (assuming you have greater than the financed amount earning interest)…
Interest isn't the killer, it's the insurance. When you owe money on a car, you're typically required to hold full coverage insurance on the car. That is not cheap.
