https://github.com/sentriz/gonic is a very lightweight implementation of Subsonic (so you can use any Subsonic client with it, ie. there are native and browser apps). I use it with DSub on Android.
There's still https://bandcamp.com/ for buying music, but there are many artists I can no longer buy mp3's from now that Google Play Music is gone :-/
There's still https://bandcamp.com/ for buying music, but there are many artists I can no longer buy mp3's from now that Google Play Music is gone :-/