M.G.
What about going to a sports store and just getting him something for his room with his sports team on it for around that amount (sometimes you have to go over slightly).
My older boys at that age liked posters, books, magazines, water squirt bottles, plaques, banners, anything like that (decals, etc.) to put on their walls in their rooms of their teams.
I like the magazine subscription idea chacha had. Kids love getting stuff like that.