Help buying a car for college student

I'm looking to buy a used car, pay under $10k (preferably <$6k, but I've been told that at that mark the cars are 100% problematic), without getting scammed and without huge costs popping up after purchase.

Can you tell me a good way/place to do this in Houston? I'm a student and need a car to drop Uber costs and to get me from point A to point B, as safely and cheaply as possible. Appreciate any help!

edit: will pay cash, no loans, etc.