I have a friend who went with a recognizable POD publisher. That publisher set the price of the paperback and the hardcover books. My friend had no say. She was priced way out of range and had difficulty selling those books, except for the meager few free copies she was sent. Who is paying $22.00 for a paperback and $33.00 for a hard copy today? She has changed publishers now, but that's a hard lesson to learn.
In my case, I was given the publisher's cost, plus shipping, as a zero profit figure. I was then able to price both my eBook and paperback with a reasonable margin. However, it's the pricey extras that will kill you. I compared one (they shall remain nameless) publisher's low cost option to their first step up program. The difference was $800. What did the author get for $800? The author's book was made available in an overpriced hard copy book, one-hundred copies of promotional materials, and the Look Inside the Book feature on Nook and Kindle. You can design and have all the promotional materials printed for around $160. Many publishers offer the Look Inside the Book feature at no charge. Remember, overpriced hard copies don't sell.
Shop around. Read the whole contract and all the instructions before you sign up. How many books do you have to sell to earn the extra $800.00 in profit? The add-ons can go as high as $10,000. But it's only money. Right?