Printed books don't fluctuate much, if at all, either.
I can't remember the last time I paid full price on a printed book. It's not unusual to get a a % of some sort even on newly released books - at least in the UK
yeah, the ibooks store is not like amazon - there seems to be very little .99 cent books or non-public domain freebies
In the US books are almost always on sale as well. Even new releases can be found at at-least 10% off on plenty of occasions.
I prefer the look of the iBook reader to Amazon reader. I just load my EPUB books (non-DRM) into iTunes. I use Calibre so conversion into EPUB is easy if I have the book in another format. I rarely buy books because I have such of huge stock-pile of free books to go through.