Bargain eBook Hunter: You can notify them of your free promo (at least a week in advance) but there is no guarantee of placement. You can pay for a guaranteed placement.
Centsible Reads: Multiple options. Daily feature for $25 and Sidebar ads $25 for a month.
eReader iQ: You can purchase a Book of the Day sponsorship for $50.
Free Booksy: Many options. They also have a free Author Marketing App for Facebook.
Frugal E Reader: Multiple options from $10 to $100 depending on promotional package choice.
Good Kindles: Requires a $1 donation and follow all of the instructions at this link to the letter.
Kindle Author Free Book Promo: $20 per title, per day.
Kindle Author: Book of the Day $75, Free Book Promo $20, Bargain Books $20.
Kindle Fire Department: Must have 3 reviews. $75 a day. No erotica.
Kindle Nation Daily: Multiple options ranging from $29.99 - $179.99.
Kindle Spice: Multiple paid options for sponsorship for erotic & erotic romance books.
Super E-books: $20 for a catalog page on their site, $45 for a daily ad, $125 for a week.
World Literary Cafe: $40 for a social media book buzz promotion. They also have a new release program for $45.
FREE