Is Amazon Losing Its Mojo?

I used to expect at least 40% discount from Amazon for most books.  Now that is no longer the case.

Tonight, My wife brought home a copy of Roadside Geology of Oregon from Costco with a $15.99 sticker on it.

Tonight’s Amazon price is $21.17 which does not even make it to 20% off.  

Yea, I know Costco is not a bookstore but this is a strong reminder that it can be worthwhile to cruise their book display and that Amazon is perhaps not always giving you the deal it once did.