I have heard about people who outsource the writing of the books they're putting up, but I don't really understand how that works. If you are going to make more money off the book than you pay the writer, then why do they need you? Why couldn't they ghost writer just publish it themselves? And if their price is really cheap, well you're probably going to get a very low quality piece of work.
Me, I want to be the creator, the one responsible for that new literary work of art. If there is a poor plot or weak characters, those need to be mine, not someone I hired on the cheap. If it were some high quality work, they probably wouldn't sell it to begin with.
What genre are you in with this? Non-fiction? Erotica? Horror shorts?