From an email from Amazon.com:
Greetings from Amazon.com.
You saved $7.00 with Amazon.com's Pre-order Price Guarantee!
The price of the item(s) decreased after you ordered them, and we gave you the lowest price.
The following title(s) decreased in price:
Inception (Blu-ray/DVD Combo + Digital Copy)
Price on order date: $24.99
Price charged at shipping: $17.99
Lowest price before release date: $17.99
Total Savings: $7.00
I was willing to pay the $24.99 but I will certainly take the extra $7.