Do you take the cars to a mechanic? How much does that cost? are there other ways to assess it besides comparing to Edmunds?
Every car model has its own quirks about what fails. Check car forums online for common failures. On every model more than a few years old, there is exhaustive documentation on any problem the car will have if you put in a good search. Use this resource over sites like edmunds, they generally have only information like "gets good mileage, is japanese and is therefore the best" etc. Sources that have info from people who actually own the cars are best.
My first recommendation is to get a friend who knows cars well to go see the cars with you. That will give you a great chance to learn the tricks of used car buying from someone who is experienced. But if you have to go it alone, here is a list of inspections you should be able to do:
-Check engine oil - level should be good and it shouldn't be jet black, should be a little brown color left when you wipe the dipstick on a paper towel. If it is this is a warning sign that the oil wasn't changed often enough
- Transmission fluid - level should be good (this is a check you do when the car is running for an auto). Smell this fluid. If it smells burnt, it isnt a good sign, but not necessarily the end of the world.
- Coolant - check the radiator and the overflow bottle levels
- Shocks - push down quickly on each corner, the car should stop traveling once it reaches the top. If it goes up then back down a little then back up, the shock is probably ready to be replaced.
- Ball joints - put a foot on the top of the wheel on each front wheel, and push hard toward the other wheel. Nothing should happen, if you hear a clunk or the wheel moves, a ball joint is likely worn.
Get Dirty!
You'll want to get a look under the car to check for leaks and rust.
Look for oil leaks - you can wipe some on a rag and look at the color to determine what it came from. If the coolant was low check for coolant leaks as well. If you find a leak, attempt to determine where it originates. This is where that internet searching on what failures are common to a model might come in handy.
Check gas / brake lines - my experience is that auto makers make gas and brake lines out of the cheapest steel you can buy with money, so they rust fast. Check these lines, if very rusty, you have a price negotiating point.
Bring a flashlight and a rag and remember its more cost effective to get a car with cosmetic issues than a good looking car with mechanical issues. Good luck!
