Super D decided some years back they would corner the market on media retail fronts on the net outside of Amazon and went around buying most of the internet-only shops. They are the largest media distributor now in the Western hemisphere. They use bots to price items at their various eBay stores, but since they carry most of the available inventory for many niche items, Super D can largely dictate pricing on less popular media items.

They are the media supplier for much of Amazon's inventory. Any release that Amazon doesn't deal directly with the studio on likely goes through Super D.

R.I.P. to BioH.
Their site now redirects to Deepdiscount, and their ebay is now called "Popmarket previous Blowitoutehere".