In reply to 02_BenYEAHmin_28.

You're in great luck. I've written quite a bit about boxes which may help you narrow things down and pick what's right for you: https://boffosocko.com/research/zettelkasten-commonplace-books-and-note-taking-collection/#Boxes

Watching local sales on eBay and Facebook Marketplace have been the best and most economical routes for me so far, especially for the bigger boxes. One filing cabinet came from a secondary market office furniture company that buys and resells furniture.