Not Amazon at all. It's a 3rd-party or Marketplace seller, who sets their own prices independently of Amazon. They simply use Amazon as a storefront.

Oh, and the super high priced fixed-price auctions on eBay are most often when sellers are out of stock, but don't want to take down the listing then have to pay to relist when the item comes back in stock. It's lazy but effective inventory management.

Source: I'm an Amazon, eBay, and independent website seller.