[No longer under development! See the Author Showcase plugin for similar, extended functionality.] Buy This Book allows authors to display their books
Turn your website into a book marketing machine! TotallyBooked allows you to add books, purchase buttons, and extras to your site in minutes.
A simple widget for adding links to your books for sale on sites like Amazon, Kobo, Nook, etc.
EZBuyButton Buy Book Widget for Authors plugin allows you to embed the EZBuyButton on Posts, Pages, and on the Sidebar. EZBuyButton is a "buy now
The Author Showcase plugin allows authors to display their books, with buy links, on their website in a nicely formatted style.