While Amazon is charging $39.19 for the Kindle version of my international tax book - not much of a price difference from the hardcover version - Barnes & Noble is charging significantly less for the Nook version. $27.99, to be precise.
Yes, I recognize that Nook devices are not quite as numerous out there as Kindle readers. But the Nook app is generally available, at least for iPads, iPhones, and the like.
UPDATE: I sent Amazon an email noting that the Nook price is lower - and, lo and behold, Amazon has now lowered the Kindle price for Fixing U.S. International Taxation to the same $27.99. See the link here.
That's definitely a hurrah, from my standpoint. Though this is up to you not me, I am hoping that it prompts some sales.