I was able to get a lot of information and act on it because I spend a lot of time on DVDTALK.

A lot of time it is pricing error by some websites ( like getting E.T. gift set for NT 800 ). Otherwise, it is because I get gift cards from time to time which I can use to get free DVDs. So even if you are in America, your mileage still may vary. Just like some people were able to get Star Wars 2 for 9.99, but others are not so fortunate.

Several years ago, when there was news about Walt Disney planning to release certain Animations on DVDs, some people was able to take advantage of Amazon's pricing errer and get titles such as Beauty and the Beast, Lion King and Snow White for free once they are released.