A new online scam is picking up speed and is particularly active during the holidays: GrinchBots. There are many limited edition products, from special sneakers to collectable toys. They can be in very high demand compared to the available supply. That is where the Grinch comes in. The attackers use automated tools to buy up almost all of the inventory of the items, then re-sell them at a huge markup on sites like eBay.
Unfortunately there is not much you can do to protect yourself, but retailers can make it much harder to launch this kind of attack. If you think a site has been hit by the GrinchBots, let them know that you are not happy and demand that they improve their anti-scalping technologies. There are solutions that work remarkably well.
I talked about the difficulty of catching these scammers in THIS article in the Boston Globe.