Adding to Crosbie’s good comments about tip jars, my ideal music player / library would have the tip / payment tracking built-in at the player level.

In web terms, if the song is fundamentally a web page, and it includes a link to a tip / pay mechanism, the player would recognize that as *part* of the song, so to speak. And, in the way a web browser tracks page history, the player could track links to your tip / pay receipts, again, as *part* of the song.