I didn't realize that we had librarians here! I may need to pick your brains about a project that I've been kicking around. I live in deep south MAGAstan (Alabama) and our libraries are under attack right now. I've got a small group who are trying to figure out the feasibility of stocking a bunch of the little free libraries with the books that are being banned from the public libraries. We just aren't sure how to source the books without spending a fortune.
Not sure about sourcing as suggested, but consider including flyers with information about the various libraries which are offering free memberships (usually to people under the age of 26, I think?) for unfettered digital access to books to nationwide borrowers. There were at least five the last time I checked. Maybe to avoid drawing desecrators’ attention you could just frame it as “need something you didn’t find here? Try these Public Libraries” & include access information below.
Not a librarian, just a supporter and citizen advocate. I'm afraid I don't know how to magically make hard copies of books cheaper. I don't think library books are usually cheaper, anyway. With the book jackets, labeling, and cataloguing, library books cost more than the same book at the bookstore. What's cheaper about library books is that the library buys them once and then circulates them to many people.
For online access, however, here are a couple things you could publicize. Maybe a QR code or URL on the little free library?
Brooklyn library, among others, has a program to provide online access to teens all over:
https://www.bklynlibrary.org/books-unbannedThe Internet Archive has an Open Library site, where they've scanned and digitized many physical libraries and many discarded and secondhand books. The results are available for download if the thing is old enough to be public domain and for online borrowing if it's newer. I think they deliberately hold off on some of the newer stuff, but it's often very good for older stuff, including out-of-print books.
https://openlibrary.org/ or also with a bunch of other fascinating stuff like old records and radio shows at
https://archive.org/ Internet Archive founder Brewster Kahle blurs the line between genius and crackpot, in a good way. His mission, as he puts it, has long been to "lock the doors open." He's about as anti-censorship, anti-book-ban as they come.
Good luck, hang in there, and don't underestimate the power of telling kids someone doesn't want them to read something, to get them to read that thing—or anything, really. (There's a quintessential clickbait headline, "Secrets [the government/the banks/big companies] don't want you to know!")