I've only seen these sets available at Toys R Us but I would imagine some of the major box stores have them too. The important thing here is that it is an "authentic jersey and card" and not an "authentic jersey card." This product is a sort of Frankenstein monster of a base card and a piece of jersey riveted together in cardboard.
Once you open up the outer wrapping you are faced with a white envelope:
I bought two of these sets. The first had a 2003 Donruss Roberto Alomar with a white jersey piece.
The second card had a 2004 Donruss Team Heroes card and a blue jersey piece.
The reverse side of these cards shows that they are made by a company called Vintage Sportscards and that these jersey pieces were obtained from Upper Deck.
Besides the problem that these are odd sized and can't really be stored easily it really only works for collectors of a certain player or team. I imagine I would like these if they had a football version with Green Bay Packers players.