Buying a new car isn't necessarily a stupid idea from a financial perspective. It's true that cars depreciate in value at a ridiculous rate (which starts the moment you drive off from the dealership), but buying from a private seller means you have no way to tell if the car has been maintained properly. I've heard that a decent number of car owners don't even get oil changes on time. Is it worth saving, say, 30% up front but risking that the car will drop dead at any moment? Maybe yes and maybe no. It depends on how reliable you need the car to be.
I bought a used car a couple months ago, paid $20 for a experian autocheck report on it and it came back with all the service records and accident history. Took it to a mechanic who ensured the car was in good condition. Since it was private party, i paid less than kbb value for it $22k compared to $28k(dealer price). Thats more than 30% savings. And if car is still under bumper to bumper warranty, you can go get a factory extended warranty for $3k and it will be the same as a certified preowned dealer car.