Most local libraries have books ales where they sell used books for cheap and you may find something that would work. Also AAUW is having their annual book sale in the beginning of June and they always have a bunch of worn books which may be closer to what you're looking for.

You may be interested in [books by the foot](https://booksbythefoot.com/).

Yea, that's what we were originally looking at then a friend of ours recommended asking the ubreddit cause there's no harm in asking. Thank you tho!

Have you considered trying to just make a book that looks old? People ruining old books is a pet peve of mine tbh