Looks like only Blue Christmas is free. You have to pledge at least $15 to get Christmas All Over Again and The Christmas Song.
Apparently they were available for streaming on Purevolume over the weekend but only Blue Christmas is still up. They have a sample of the Petty cover on their Facebook page which sounds pretty cool.
I'd buy the tracks individually but can't really afford the $15 right now.
Yeah, I figured that out as well, and it's slightly disappointing. I don't have $15 to drop, but I could drop $2.