I use CreateSpace, and as Blueberry said, they show the minimum price you can sell a book at. There are several paperbacks that I only make about 50 cents per copy. That isn't really enough to make back the costs of the cover, for example, unless a lot of books are sold. It's one reason why I've done a lot of anthologies, which I can price cheaper, but because they have fewer pages I'm still able to cut off some of the losses from the other books. Still, anthologies are a very hard sell, so this isn't a long-term solution.
I'm aiming to diversify revenue streams in 2017 and 2018 with some new product types (and probably some ebook-only versions, since paperbacks have been hard to make money back on).
To Tom's point, I'm not looking for a huge profit. My goal is primarily to not lose significant money on book releases; if I can make a profit, that's nice, but I don't really expect it. Of course, if this were my only source of income, that's untenable. The main goal of EBP is to help talented writers build and develop an audience. It's very much a labor of love.