A slight 'detour' here - if you(all) did a book through ACX on the pay for production deal, and you are on the exclusive ACX contract, you can revert to non-exclusive after one year. That will allow you to offer your book on other sites (like gumroad, cdbaby or bandcamp) at your own price point, or offer it free. But if you did royalty share, you can't.
http://www.acx.com/help/contracts-agreements/200474550#change-contract
Authors with a series might consider putting their first book in non-exclusive, which gives them (the rights holder) the ability to do giveaways, discounts, beyond the ACX codes, and sell on other sites (at the expense of lower ACX royalties - so that book becomes your ACX loss leader). I suspect several authors here have passed the one year mark already. Maybe Jeffry you could do the free book of the day, for example, exclusively for your subscribers. I would be happy to offer one of my books as free for a day. I think it might be cool also to do something like a weekly contest to win a free audio player pre-loaded with some of that weeks audiobooks.
Thanks again and darn it this is something I was thinking of doing!