Many of my clients sell books at book shows, state fairs, seminars, and other events where they are face-to-face with readers. Selling in person works great when you have a physical book and the reader likes physical books. Some readers, however, prefer e-books.
Telling someone your book is available at all the major e-book retailers isn’t good customer service. The buyer wants the book now, not later — assuming they’ll remember to look for it later.
At least two companies are now making e-book cards. Each card has a redemption code on it, just like the gift cards found on kiosks at stores. Book buyers buy the book card from the author/publisher, go to the website shown on the card, enter the redemption code, and download the e-book.
I haven’t used any of these services, and I’d be interested in hearing from authors, publishers, and readers who have.
Updated 10/20/2013 to add an additional source.