I've spent over 15 years working in automotive retailing, and ... pros in the business agree ... cheapest way to live is to buy them slightly used, keep them maintained, and ... drive them into the ground.
'Course, if everyone did that, none of us could have made a living in automotive retailing ...
There is the rare exception. *We try to buy Toyotas. *Like Southwest Airlines, they're cheap, and they get you there without fail. *But ... when shopping for a slightly used Camry, we found the used models were almost as expensive as new, and very tough to find on the privately owned market. *So, we bought new. *In that case (1 year ago), financed with a 4% credit union loan. *Paid off the loan anyway, but new was the way to go in this case.
Another cute trick, if you don't drive much ... buy a classic. *Buy the right, older car, and you may not make much money on the investment, but it will probably at least break even. *But don't pile on the miles, and baby that car.
Last piece of advice ... watch those old luxury cars. *For grins, call the Lexus dealer some time and tell them your power windows, seats, or some other hi-tech component has gone out, and ... the car is out of warranty. *The Lexus is one great car, but like all premium luxury models ... when they break, and it is out of warranty, those are some very big numbers.
By the way ... yes, car dealers do make a lot of money on the "back end" ... the F&I portion of the car deal. Old rule of thumb was to make $1K on the front (gross profit on the sale of the new or used car), and $1K on the back [finance reserve (dif between your interest rate and were we borrow money), and profit on extended service contracts, etch, gap insurance, etc.]. To be fair to the dealers, it is still a competitive business ... good domestic dealers only make 3 to 4% EBITDA.
Good luck ... fun subject.