The https://coderanch.com/how-to/java/AndroidFaq has a partial and outdated list of alternative stores. Searching for "android app store" or some such phrase will undoubtedly find more. Not distributing via the Play Store will several hamper the reach of any app, though. Its cost used to be USD 25 onetime for unlimited apps - an insignificant amount given the time you invest in any nontrivial app.
Post by:autobot
Just let me do the talking. Ahem ... so ... you see ... we have this tiny ad...
a bit of art, as a gift, that will fit in a stocking