What kind of computer do I need for Gary's mod?

[Operamo]

I'm trying to find out what I need in a computer to be able to play Garry's Mod? I am pretty poor and was trying to Find a computer for my son for Xmas where he can play this game.

 

[ffg7]

laptop or desktop?
http/www.systemrequirementslab.com/cyri/requirements/Garrys-Mod/11441/?p=r