I am just now checking out the Kindle Countdown Deals Promotion Feature for some of my books. It seems to be an interesting way to promote your book and works by setting a start price (usually .99$) and an end-price (which is your current list-price). During the promotion period there are several price increments.
See the schedule for “The Definitive Rules of Management!” here:
I am interested to see how this works out in comparison to make your book available for free (the other Benefits option for your Kindle Book). An interesting difference for this promotion is that you have to manage it for each marketplace seperately, however I was only able to set this up for the US and UK marketplaces.
I’ll keep you updated about the progress.