There is a pick of three editions of Waiting for Regina. If you look below in the screen shot on the right side of the image of the Barnes and Noble's page of the electronic version of the novel. You see a distinction of prices. The Nook book is an epub, and it is also the first published 157 paged edition of Waiting for Regina before the recent revision.
There are paperback and hardcover editions of Waiting for Regina, these are the revised versions of 186 pages which include added content to the novel, a table of contents, and short author biography. I left out the additional materials last year to reduce the cost of producing the book.
You can read the entire book for free if you visit a Barnes and Noble bookstore repeatedly. That would be after a customer is downloading the free ebook on a tablet or smartphone. You have to read it in the store. The publication will disappear off your tablet if you return to your car in the parking lot. There are also digital formats of the first edition book on sale at Smashwords including Apple iBook.