Couple things... Is this a dealer or a private party? If its a dealer car then ask about their inspection. If its a private party, you'd need to get a pre purchase inspection when you get really serious about the car.
My advice: go on a long test drive. See what the car is like in traffic, on the freeway. Try to turn everything off and on and make sure everything works. Do a search on "used car checklist". And hopefully you'll be able to print out a blank checklist. Read over that list, look for those things when you're with the car, and fill that thing out as soon as the meeting for the car is over. I still have checklists in a folder from when I was looking for my BMW.
yr, make, model, asking price, trade in, wholesale, retail (
www.kbb.com, www.edmunds.com), mileage, maintenance records?, paint/body condition, mechanical condition, tires, wheels, options, other extras, repairs needed?, etc.
If you don't want to pay too much, this is the best way to go about it. Good luck.