If you go the traditional route of sending your book to a publishing house, they will set a wholesale price (what the book stores pay) and a suggested retail price (what customers pay) for the book.
The book store can charge whatever they want. An independent bookstore will probably charge the suggested retail price. A chain store may mark it down.
But -- you are usually allowed to buy your own books from the publisher at a discount (usually half price) and you can sell them at whatever price you like.
If you self publish (you pay all the costs of publishing your book) then you can set your own price. But book stores generally won't carry a self-published book and reviewers won't review one, and you usually end up with a garage full of books you can't get rid of.