I doubt, I hope I am not to blame. At least I hope not…
The reality is that most books plummet in prices very quickly now after release. Actually, so do CDs …when I buy a CD as a pre-order on Amazon it is common for the price guarantee of Amazon to kick in and reduce it below the pre-order price before I even receive it. Amazon really have a good thing going in terms of enabling what is likely the vast majority of the resale market for books (well maybe eBay also).
As an indication of the change in value of books from release to buying a discounted or used version of a book I can look at my authors profile on Amazon and see the price for a new copy, a discounted copy and used copies.
As an example of the discounted books available a partial screenshot is below. The book regarding Collaborative Computational Technologies must have sold really well because there are lots of used copies for sale it seems! At just over a $3 starting price. BARGAIN…grab one for each of your family members….