What should I get for christmas for guy I know only 3.5 months and...

If you know what he likes, (for example a movie that he likes but doesn't have) If you don't know what he likes, find out. I had the same problem. I like this guy and have only known him for a month. But he gave me a present, so I wanted to get him something too. I didn't know what to get him. I knew that he liked video games and we had similar taste in movies. As I was looking, I remembered that he said he liked the movie Battle Royale and at one store there was a box set. So I asked him if he owned it and he said no. I ended up getting it for him and he loved it ^_^.

It doesn't have to be a movie, but ya just an example. Also, try not to get anything too expensive. You haven't known him that long and it may be awkward for him. If you can remember your previous conversations with the guy, try to remember if he said something specific that he likes and go from there. Good Luck! ^_^V