There are a myriad of resources on the Internet on this subject. Most folks are novice at it and choose to avoid doing any research so you're probably further ahead than a good deal of used car buyers out there. The problem is there are people (sellers and buyers) who do this all day on CL.
I would do a few things before you buy:
-Check KBB for what the range of fair prices should be.
-Look for common problems with that make and model. You can start with googling "1998 Honda Accord Problem" and see what comes up. If you're more savvy, look for websites that aggregate common complaints, repairs, recalls, etc. If you really want to get into it, there is a forum out there for almost every car. You can browse it or join it and ask questions about things to look out for. The key here is to come armed with specific questions. For example, if I were buying a late 90's subaru, I would ask whether the seller had the valve cover gaskets replaced. It's a specific enough issue that you can't sidestep the question to hide issues.
-When you get the VIN, run a carfax or similar to verify that it has a clean title.
When you see the car:
-Ask questions! Use your research and go off if what you see. When was the last oil change? Do you have service records? What's the gas mileage like for you? Keep the seller from trying to sell you the car. The car should be the one doing the selling.
-Take it for a test drive that covers every type of road. If you can work out with the seller to drive it alone, do so. It's better to not have them try to explain away every issue. If not, be very attentive to how it drives.
-Get it inspected by a mechanic if you dont feel comfortable looking it over yourself. There are things that you won't be able to see that they will.
-Wait a day or three before pulling the trigger. Think about how it drove and whether or not you feel comfortable in it. Was the driving position okay? Good visibility? Don't make any compromises in the moment. Think rationally and make sure you're getting a good deal and will have something that will last you a long time.
