As ridiculous as that price looks, it's not totally out of the ballpark. Last year, just before Botcon, a dealer on Ebay sold a set of the 2 "common" Dino combiners and it went for somewhere around $1400.
Be aware, they make fake AFA by opening the original case, replace the content and re-seal it. This seller is suspicious to be involved in such nasty trade.
This seller is definitely shady. I confronted him last week because he had two Dinobots afa on auctions and the same user who won the first time was still the highest bidder. I ended up reporting him and his auction was taken down after that.