Personally you got to know yourself. If you plan to race with it, 4x4 with it, party hearty with it, and go on many trips to nowhere and yet everywhere.... then a new car is not the route I would go(only because you are going to destroy the first couple of vehicles) and that is a lot of coin to lose in repairs on a first vehicle.
Grab a few books on mechanical repair, how to do it yourself stuff. Not that the cars you are going to buy are wrecks, but all cars break down....and with the older models(pre computer era, you can at least fix them on the side of the road without anymore tools than a good set of wrenches and screwdrivers and a repair manual. Or a good memory.
Cars break down. Does not matter if it is new, or experienced. Except when it comes to initial cost and the cost of repairs. Insurance costs will be lower on an older car as well.
Get used to looking at used cars in the paper. What kind of car...that would be unrealistic to expect to get the right car on the first go. Every car has its good side, its personality side, and its negative side. Personally, I would buy an old time VW Bug again(3) if I could find one. But if they were asking an arm and a leg for it, I would take the station wagen model(type3)(3) as it is more useable(I can camp with it & sleep inside) I know they are not race machines, but hey, I like to go fishing, skiing, bushing, prospecting,. And I won't have to worry about getting the seats all dirtied up or the paint scratched. And should the car ever get stuck in the snow, slip it into gear(I drive standards) and get out and push it out myself. No use getting the big old heavy V8 monsters unless you own an oil well. Parts may be hard to score initially but you will make contacts and they will know somebody and so on. 30 MPG can be expected which is decent. I have picked up cars from the back of autorepair shops that did not want to work on them for $400 (because it was running on 3 cylinders) Took home fixed it (mainly time involved) and right away when running right was worth $1500....and drove the car for 4 years afterward, before selling it for something else.
There is the new generation of cars on the street now, and the older generation(they had rain gutters above the side windows). The older generation ones are the ones that are most likely not as much computerization. If you can get something with less than a 100,000 miles on it, you got wheels. Sure there is no air bags, but air bags are not gonna save you if it is a spectacular accident anyways. Seatbelt will help though. Old Toyotas, will do the 100+. I would tend to favour the 4 door model just because it is convenient for hauling stuff in the back seat. Just open the door and put it in, rather than flip the front seat forward and squeeze it into the back.(that goes for people that have small bladders). So great if you got tools or equipment to take to work.
More responsible family type people tend to drive 4 doors so you know it has not been "bagged on".
Chances are they took it in for regular maintenance more often.
I always make private sales. Not car lots. Sure, there is the "buyer beware thing" and you lose if you make a bad buy....but homeowners are not as savvy as car lots on hiding the imperfections. And see the car twice(one day in the rain) and it is parked in the rain -if it leaks inside, you will know//and the next time on a clear day so you can eyeball the bodywork and the paint job closely. If the engine makes weird mettallic clunking noises while running and the owner tries to explain it away, walk away. Unless you got another engine to throw in.
Car buying is both fun and a challenge . It would help if you knew what you needed. If it is a rust bucket, again walk.
Also check Consumer Reports back issues as they rate cars all makes. and mark out the good bad and the ugly.
I know many say, once over 60,000 miles it is toast. But it all depends on how it was driven. Police cars are given up at that time and Taxi companies bid for them. And can put over 200,000miles. And if I had a chance to buy a Hemi Cuda from the muscle car years, mileage don't matter. Everything is replaceable.
My car I got with 80,000 miles and I got rid of it after "740,000" miles as the body rusted away ( a diesel VW Rabbit) and I sold it for what I initially paid for it...and it was still running fine. I learned how to change timing belt myself so that was a $40.oo cost for the part (a few belts worth)and some time on the weekend. I had gotten a decent manual about the car with lots of photos and proper metric tools. If I needed a part, an autosalvage yard is where I shopped most times. Used parts for a used car(just in better condition than mine)