I wonder if it is because it is reasonably priced on Amazon instead of the Apple Book Store hostage prices of $14.99 and up.
Just get it on the Kindle App, only like $7 per book.
I noticed this as well...but at least the Kindle app will let you buy it.
Now if only Harry Potter were finally released in eform I would be so darn happy lol. I don't care that I'm in my late 20s, those books will always be great
Here you go, Brandon:
Harry Potter ebook Rentals Coming Soon
It mentions sales down at the end of the article. No date yet though.