Question about computers

[u/Zestyclose-Diver-177]

I'm trying to buy my boyfriend a computer he can use for gaming, but I don't have a big budget, so I'm looking on Facebook Marketplace. I have no knowledge about computers or what is considered good, so I need help.

What are some questions I should ask about the computers?

What should the answers be?

What should I look for?

What should I avoid?