The dev, @hariette, also has a Mastodon profile where she posts updates https://tech.lgbt/@hariette. There is also a link to the apps discord server in her bio.
Apollo did have a free tier and then a few paid tiers.
iirc, (I bought it many years ago), they had a one time Pro purchase that removed any ads and unlocked theming and such, and then the Ultimate which was a subscription to cover server costs of push notifications (although it did eventually end up having more features locked behind it).
While I personally did not go for the Ultimate subscription (didn’t really need the push notifications), I gladly paid for the Pro as it was well worth it IMO.
Yes, I meant freedom and not price: https://youtu.be/Ag1AKIl_2GM
We want to be able to make sure the app doesn’t do anything malicious (like spy on us) and be able to change it to fit out needs. Like we can with Lemmy.