LEGO pricing in general has been inflated recently. Flippers and 3rd-party Amazon sellers know this, so they buy up all the stock to resell via Amazon FBA. It's a LEGO bubble right now with a lot of artificial demand. Some of these flippers will coordinate massive regional buyouts of a given LEGO set from retail stores by using people from Fiverr, etc. and then hoard the bulk lots or sell to collectors.
Stores are even being robbed of LEGO merchandise:
http://www.dailytelegraph.com.au/news/nsw/story-fni0cx12-122...