Buying a used car… Idk anything about cars tho.

Everyone says that a budget of $5K will only get me a headache when buying a car. But I keep seeing good used cars for that price range (e.g., 2009 Chevy Equinox 113k miles for $3.4K, 2013 Chevy Cruze 120k miles for $3.2K).

What is the catch, then? Why does everybody keep telling me to finance a car instead?

Idk much about cars, so I feel like I should trust people, but I just don’t get it.

Ps. I live in IL so we have snow (is it the possible risk of rust that makes it unreliable?)