At the Browns game we were running late so I didn't experience the Lambeau Lot, but there was a guy on the corner as we crossed the street selling tickets. As we passed by, he was talking to a couple and said he'd take $15/ticket.
FYI in case anyone wants to show up for the next pre-season game without tickets. The market will probably remain soft. At the same time, while demand may be down, last Saturday was one of the better crowds I've seen at Lambeau in recent memory (wasn't much to cheer about last year). You won't be cheated out of the "Lambeau Experience" for going to a game that doesn't count.