
I am a denizen of marina book exchanges. I have been for several decades. eBooks are changing the game a bit. So I spent some time thinking about how to benefit from and contribute to the change.
I just published CATANGO, [Happy Birthday to me] and here is an advertisement I leave in marinas and other places with cork-boards (asking permission of course, since sales are involved).

It’s the size of a business card and scanning the QR code with a smart-phone takes one to the Amazon Website where one can purchase the book. If the smart-phone has the Kindle App loaded, the book is in hand almost as fast as pulling one from the exchange. The purchaser doesn’t even have to remove the card from the cork-board.
If you have a book to sell, eBook or not, I suggest you may want to take advantage of the technology.
To do so, there are a variety of services for converting long web-addresses (such as those from Amazon’s Store) to short URLs and QR codes. I used:
http://goo.gl/
I inserted my Amazon link and instantly received the shortened URL. Clicking “Details” provided the QR Code. Clicking the link under it provided a higher resolution graphic. This I copied to my business card software. Viola!