Christmas gift for girlfriend?

My girlfriend of a year and a half likes to read and write. She also loves music with a passion. I have a budget of 100 dollars and I want to get her something cool and usable yet something I can personalize and make sentimental. I was going to get her an e-reader and fill it with scanned love notes I had written her in the past, along with a few pictures of her and I, but I found out that her parents are getting her an e-reader already, and so I'm kind of lost. I had a few ideas, but what are some cool things I could get her that involve reading, writing, or music all within that budget?