What Should I get him for our six month anniversary?

Our 6 month anniversary is coming up soon but we won't be able to be together since I will be out of town. I was going to give something to his roommate to give to him on that day. I don't wanna spend much at all but I want it to mean something to him. I was planning on writing a note about how much he means to me and such. And then I thought about makin a CD of songs that reminds me of us. Is this a stupid idea? Do you think a young guy would appreciate this or should I do something else? What would a guy in his late teens want? Advice?