Here's how you do it:
- Publish the eBook with Smashwords (they are one of the few retailers who allows you to change the price of your book to free)
- Choose to distribute it to all sorts of different retailers, but especially Nook (Don't publish your own version directly with Nook)
- Copy the Nook link when Smashwords sends the free eBook over (it'll take a couple of days)
- Go to your book's page (the one customers see) on Amazon
- Scroll down to Product Details on your book. At the very bottom, you'll find this: "Would you like to give feedback on images or tell us about a lower price?"
- Click on the last link in that sentence
- Fill in the necessary info (linking back to Nook)
- Have a few other people do this too, if you'd like.
It usually takes two weeks to a month for Amazon to drop the eBook to free. For me, it was two months. I had one friend whose book price was dropped in a couple of hours (but don't expect that to happen to you, because it probably won't). It's very, very, very important to note that you should not schedule any promotions that will be based on this free eBook until after Amazon has price matched. It's nearly impossible to predict how long it'll take for them to drop the price, and some authors are reporting months of waiting now.
And that's it! This isn't a temporary way to promote - you'll want to leave the book for free for a while to gain the benefits of having a permafree eBook.
Having a permafree eBook works best when it's the first book in the series. You'll make your money on the following books in the series. Don't think about free downloads as money lost, think of it as readers found who wouldn't have downloaded otherwise.
This sort of thing (and many other awesome tactics on self-publishing) will be taught at the upcoming Indie Author Hub conference on June 7, 2014. (That's a Saturday.) Learn more about the conference here!