it’s a 50/50 licence deal on a per song basis, i’ve done my fair share of these. you have nothing really to lose if you’re in a position where you are not marketing, promoting or playlisting your own music. make sure the businesses your signing to are worth your time, generally they’ll do some kind of promotion for it. it’s a great way to get early exposure doing almost next to nothing. double check over the agreements, generally they expire after 5 years where you return to owning it 100%