How does the TCM Shop do it?

So I was in Sam's Club the other day picking up some of the brand-name stuff I use in bulk. They had a section of DVDs and Blu-Rays up. There was a lot of recent stuff, which isn't surprising, and a lot of collections that look like stuff that's fallen into the public domain, which is how you can get them so cheaply. But there were also some of the box sets that you see hawked on TCM between movies. There were a couple of those four-movie sets, but also a copy or two of the Warner Gangsters Collection, Vol. 3.

Now, I've seen all six of the films in the collection, each on its own individual DVD. And I think I've blogged about five of them, with Smart Money being the only one not to get a full-length post, and even for that one I mentioned the (then-upcoming) Warner Gangsters Collection. But I decided to take a flyer on the set since it was on sale for $19.99.

So imagine my surprise when I looked up the TCM shop, and saw that the same set is currently on sale in a 5% off sale: you can get it for the princely sum of $56.99, saving a full three dollars! With all due respect to the TCM shop, but why would anybody want to pay so much more there for the same product? (The question of why 70-year-old movies cost even what I paid in the first place is one for another time.) Are the Waltons ripping off people with inferior versions of the box sets, or is somebody ripping them off?