u/Downtown-Meet-2513

I am a college student looking to buy a used car for around 6k with 150k or less miles, but I am not sure to where to look. Is facebook marketplace my best bet? I know there can be scams, and I don't know how to avoid those sellers. Also, does anyone have any suggestions for reliable cars that wont need maintenance that are in this range? (I have no idea about buying used cars obviously)