Amazon is offering it to me at 20% off plus free shipping! A mere $191.16.
The comparable edition of LeBron and Alex's book is "only" $168.95, which Amazon is willing to give me for $132.03, a 22% discount.
So at the Amazon prices, Lebron & Alex are 31% cheaper, but still pretty steep.
The previous edition of Mankiw's text did have a Kindle edition for $149, no word about whether the new edition will or if so, at what price. Surprisingly, LeBron and Alex do not have a Kindle edition (at least that I could find).
These days, given that you could make yourself a pretty good free principles text just by downloading relevant Wikipedia entries, I don't see how these rents can be sustained over the long run (I am aware that not all or perhaps not even a majority of the rents are going to the authors).