> That also means purchases are tied to the Google account used to buy the app, so unfortunately they can't be shared across different accounts.

I don't have hand-to-hand experience with Google Play, but quite a few of those billing platforms offer "discount codes." So to help the GP commenter, I would imagine they could email you from their purchasing Google account and ask for 100% off codes for their other Google account addresses

I don't know how to help the sibling comment, short of you just straight-up making them a custom .apk without Play Billing. FWIW, it's actually absolutely painless to host your own f-droid repository <https://gitlab.com/fdroid/fdroidserver#what-is-f-droid-serve...>. It's marked AGPL but despite its name one doesn't need to run that package to host a repo, just $($HOMEBREW_PREFIX/bin/fdroid update --verbose --create-metadata -W error) and then $(rsync -Pav --delete ./repo/ your-awesome-host:/repo/)

It's so painless you could even do that per user, as in lucb1e-fdroid.example.com or lucb1e-a6d7c104-e9b1-4ddc-ad5a-470e51bb5069.example.com