Buying a used car for $4000-4500?

I'm a college student at IU trying to buy a car in Chicago before the start of the school year. My budget is around 4-4.5k. I noticed that almost all the listings on cars.com, carsguru.com, craigslist.com are of cars over 100k miles. As a college student, i want a reliable car that does not cost very much to maintain. My questions are:
1. Are cars over 100k reliable?
2. After looking around, i found some options that i like which are: 05 Kia Sorento with 85k miles, 06 Hyundai Sonata with 100k miles, 03 VW Passat GLS w/ 100k, 04 Honda Civic coupe with 110k, 03 Nissan Altima w/ 108k. Which is the best?
3. Other brands (other than the obvious toyota and honda) should I consider?

1. Use consumer report and kbb.com to research what fits you. I.e. If you need thrid row or a 2 seater
2. Impress the dealer one example would be to try to calculate the mileage for the entire year is you get a 20 g tank vs a smaller car etc
3. Test drive with mechanic
4. Visit several dealers and get print out of carfax