3 pages rules are free. You need at least 2 page rules per website you want to use with Backblaze and Cloudflare, and that's for bare minimum workability.

For a commercial company paying $5-10 a month to save TBs of bandwidth via Backblaze & Cloudflare is a no brainer. It's just unfortunately not very workable for small projects. Github Pages works with Cloudflare for static sites just fine though.