I'm in the market for my first car with no knowledge of cars at all! Help!

I'm from San Antonio, Texas, USA and am not really much of a car guy but am looking for a good, (technically) first car. I generally like the designs of BMW's, but I can't really afford that type of maintenance. I am looking to spend between $7,000 to $15,000 for a reliable used car. Any advice on cars would be great! Thanks!