I ordered from Amazon and I just got an email saying they are going to refund $4.
You saved $4.00 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:
LEGO Harry Potter: Years 1-4
Price on order date: $49.99
Price charged at shipping: $49.99
Lowest price before release date: $45.99
Amount to be refunded: $4.00
Quantity: 1
Total Savings: $4.00
So, the net price will be $36 (including the $10 toward another game).