The following are just a few of the many web sites where you can promote your e-book. I have used each of them at one time or another. Their prices range from the inexpensive to the expensive.
World Literary Cafehttp://www.worldliterarycafe.com/
The eReader Cafehttp://theereadercafe.com/promote-your-books/
Kindle Book Reviewhttps://www.thekindlebookreview.net/
Ereader News Todayhttp://ereadernewstoday.com/authors-promote-your-kindle-books-here/