gust wireless access

Problem 3. There was couple of times that our neighbor asked to use our internet (they ran out of their own capacity for downloading). So we decided to let them, but even though we didn’t give them the password his laptop kind of saved it or I think I forgot to look for this check box which asks If I want this network to be saved or not. Well after that he started to use our internet more and more and we had to all the time increase our limit. So I knew how to throw him out of our private network but I didn’t know in the future how to give a limited temporary access to a person just in case so he wouldn’t have access first. To everything shared in our network and second. use all the time our internet. I mean even if we trust them we don’t know how good their own security is?