The FTC offers many different variations of free physical bookmarks in bulk. The smallest quantity you can order are 100 of them, so these might be great for any teachers or book clubs out there in HIF land.
I didn't personally order these because I didn't want to waste a hundred bookmarks. If you're only looking for a single free bookmark, then use this list of free bookmarks that I keep updated. I still use my tick identification bookmark, which is a sentence I never thought I'd utter!