I also love Pandora. It has pretty much introduced me to my music library: Within Temptation, 69 Eyes, Echoes of Eternity, Incubus Succubus, all seeded from Nightwish (I have a weakness for Nordic Metal fronted by sopranos).
I’ll give the subscription option a try. Pandora has a hybrid model, so perhaps that word work for nderground.
Ironically, even though a yearly Pandora subscription is maybe a week of coffee, lots of people will not subscribe. Nor do they buy albums from the bands they love. Unfortunately there’s a whole generation that has been taught that web applications and music are free.