Check the tire tread wear, how old the car battery is, brake wear, test all the lights, the heating and cooling, test drive it, make sure it drives straigh, no vibrations on highway speeds. look close at all the wheels, make sure there’s no curb damage. Look at the clear roof, there’s no check marks and crazing. Have the seller show you all the maintenance records. Has the oil, air filter, cabin filter been changed. Look over the body panel, the clear coat is in good order. Any wear and tear on the interior? Body scratches. How clean it is Inside it. Radio works. Strange engine vibration. Muffler in good shape, the flex joint not broken. The muffler is $$$. Make sure there isn’t a engine check lamp on. Power windows operate.
If in doubt, out of your pocket, have a good mechanic look over the vehicle. Any issues, Negotiate the sales price.
