You wrote a book. Very nice. But you didn't write to keep it for you. You should publish it. The problem is that the publishers charge high prices for some authors pockets, and do it objectively, due to the high cost of printing.
But you allowed that luxury, and now you have a printed book, with you as the author. You can keep hundreds or thousands of volumes in your personal library and give it as a gift to your friends in special occasions, or try to distribute in various libraries. You managed to distribute it, the book is beautifully placed in shelves. In time, dust is spread on covers. After a while, the book is withdrawn. It remains to use it as decoration at home, or support for various household items.
But lucky for you, there is an alternative, cheaper and more effective, in selling your book: e-Books!
e-Book and online publishing market has evolved rapidly in recent years, and a lot of companies have entered this market, as publishers, online bookstores, or promoting e-books.