That’s an very nice idea. You will get to earn money and force yourself to go through the notes again.

Anyway, you will be very busy if you have to do it for all the different classes. Another problems that I can foresee is that your “kind” classmates may “lend” your notes to the other classmates. So it may be better if you convert send your notes in pdf format with watermarks or a courtesy message below saying “If you got this for free for someone, I would appreciate if you can at least buy me a cup of coffee over school lunch.”