I see this question pop up quite often on Quora.com. The answer is, it varies. The one thing you should never have to pay for is the actual publishing. Unless it’s a local press that requires a certain amount of copies to be bought then your book should not cost a thing. Even if it is a local press you might do better going someplace without that up front cost because you will need your money for other things. Here is a post from Nathan Bransford’s blog that covers what those are. What it Costs to Self-publish a Book.