I built this because I was tired of paying for a checklist, or squinting at a blurry PDF I found on a forum. It's free, and it stays free for personal use. But it isn't free to run: there's hosting, a domain, and the email that sends your sign-in links — and I'm paying for my own IFR training while I keep this going.
If it helped and you want to throw a few dollars at the avgas fund, thank you — genuinely. If you can't right now, keep using it — that's genuinely fine.