This is an eBay listing for Amazing Spider-Man #700, in hand, for $50. It was ended early after Marvel Comics intervened.
It was listed by the owner of Comic Crusaders, an online comic book store based in Long Island, New York.
He read his copy on the 13th of December before putting it on eBay for $50 the next day. He also offered to take a photo of a scene for a writer on ComicBookMovie.com. Then he tweeted about the comic, and that he was selling a copy.
Also, it may not have been the only comic he got so early.
I speculated yesterday that the leak may be down to printer or distributor issues. However the distance from the printer and the distributor in question to Long Island – and the proximity to Marvel's offices instead – suggests to me that, somehow, a copy of the printed Amazing Spider-Man #1 and Avenging Spider-Man #15.1 made its way to him from the House Of Ideas itself.
And to who-knows-how-many people.
I think Marvel were prepared for this leake from December 18th onwards, which is when retailers would receive the comic to sell on December 26th. But nothing this early…