Try Thumbtack. I've used it, and what happens is they send you leads, and you have to pony up $2.99 for every proposal you send out. I've had mixed results with it--you wind up with people who get cold feet when it comes time to show up, folks who are not quite as talented as they like to think they are, etc. All the things you might imagine could happen. There are a lot of people out there who want to sing and rap and compose, believe you me.
Most people don't have the money to pay a more established studio, so they are looking for a cheap alternative to get their stuff out there. You wind up having to separate the wheat from the chaff--after a while you recognize that "artists" who simply want to remake a Beyoncé song probably aren't what you want to deal with. I'm on the lookout for performers who are keen to sing their own songs, or collaborate with others to come up with something new.