What is the difference between a "certified pre-owned" car versus a "used car"? Aren't they both technically "used cars"? What are some used car buying things to watch out for when you are, well ... a friggin' stupid idiot when it comes to cars? I do not know a single person who knows anything about cars. I do not know any mechanics. Whenever I had a problem with my car, my dad always took care of it; he passed away this summer. How do you make sure you don't wind up with a lemon?