Ideas for a birthday PRESENT theme?

My best friend's birthday is coming up and I'd like to get her some really nice presents. I need help coming up with a theme for these presents... for example, last year I got her presents that went along with a movie theme. I got her some movies, popcorn, gummy bears, pjs, etc. I have about $50 US to spend on these presents and we are in our teens if that helps. Thanks in advance! :)