A couple comments:
* I bought one new car the year after I graduated from college. I had a great job and didn't have any real expenses. After one year, I really hated that car payment. By year number 4, I vowed I would never have a car loan again. It was just a waste of money (I think about $5000 over the life of the loan.)
* I think there is wisdom in your situation to take out a small loan and build a credit history.
* I bought my first Honda brand new in 1988. It ran great until I crashed it in 1996 at 198,000 miles. I was in the midst of a career change at the time, going to school, and I didn't know when I would have a job again, so I bought a used Honda Accord with 92000 miles. It had a hatchback that I hated. Since there's no trunk, anything you carry in the back, like a set of golf clubs, is visible. I drove it for two years before I bought another Honda Accord 3 years old with ~60000 miles. I drove that one until it burned up in a garage fire (~150000). I replace it with another Honda Accord 3 years old that had 38000 miles.
** You're going drop a fair chunk of change on a car whether it's new or used. Make sure you buy something you're going to be happy with. For me that means a car that gets good mileage and is highly unlikely to need to go to the some for repairs. It might be that "American" cars could fill that bill, but why do I need to take the chance? I know Honda has always satisfied me on those two criteria.
* Unless you like bargaining with people DECIDE how much you are willing to pay for this car. Whether you go to an individual or a dealership, after you've identified the car that you want, tell them this is how much you're willing to pay and stick to your guns. You're not going to be able to low-ball using this tactic, but it cuts down on hassles dramatically.
* I wouldn't necessarily avoid a dealership when buying used cars. If you can get the car you want at a figure you're willing to pay, there are several benefits to buying from a dealership (not the corner lot, however). Most of the used cars sold by a reputable dealership have been refurbished - they are completely cleaned, worn tires are replaced, etc. and often come with a limited warranty. Most individuals are selling a car just before making expensive repair/maintenance decisions such as timing belts, new tires, etc. You will have to pay for those with cash in your pocket if you buy from an individual. Also, if something goes wrong soon after buying a car the dealership will often have a limited warranty that covers major issues - with an individual you're stuck.
** I've bought from individuals and from dealerships and been happy in both situations. Do your research (If buying from an individual, ask to see the maintenace records on the car. If they don't have them, be cautious). Know what you're buying. Decide how much it's worth to you and spend that much and no more.