What do you look for in a man.....dolin?

My dad has hinted at wanting to learn the mandolin, so I want to buy him one for Christmas. I’d like to make a transaction locally on a used one, so I’m looking at Craig’s List. Once I start looking seriously, I’ll have no idea how to assess an instrument.

My dad is a total beginner. He has some basic musical knowledge and would do best with a basic instrument (i.e. doesn’t need amp plug or anything—do they even make those for mandolins?).

What I’m wondering is if there is anything I should avoid when buying one. I also am unfamiliar with the instrument but I’ve played violin and guitar so I know about stringed instruments. I’d be able to assess if it goes out of tune easily, for example.

Are there various kinds and sizes? Does one country make them best?

Thanks!