Hello:
My bid for this project is for one site, a price for 5 sites would be $249 provided the additional sites use the same basic template with just differences in content, colours, images etc.
For a book website, I would recommend one one-page site per book, so that visitors are focused on the book they want to see and not distracted by other elements.
A one-page site would be ample to sell a book, you could fit all the elements mentioned below on one page, excepting perhaps the download/thank you page. If you wish, I could do up a quick concept of what that would look like.
Looking forward to your reply.
Regards
Jon