Anyone who makes claims like that has never done any research. Most of the "deals" may be rotten, but if you know what you're looking for, you can find some decent deals. A few years ago, I picked up some fine animation art, including a production cel of Marvin the Martian, and one of my favorite pieces called "A Wonderful, Awful Idea" (signed by Chuck Jones), both for less than I could find them for on land.

And every once in a while, you can get a real steal. When Michael Godard was first starting out, you could have gotten his pieces on a cruise ship for less than 10% what they go for now.