Best way to do this?

1

So taking a laptop to school has finally paid off as the slackers in the class have not been taking notes. I, on the other hand, have digital copies of all the lectures in word form. Now people are interested in buying, but the obvious problem is that i do not want to send it to a few people, and the entire class have it within a week via forwarded emails. Now i can set up a passowrd on word, but that really won’t do much good, what do you guys think? what would make it the most inconvienient to distribute besides printing out the copies itself (i don’t want to waste all the ink/paper so i prefer to stay digital)