I just received an email from the Buddig Lunch Club for a free backpack. It's to the first 1,000 members to print off the validation page from the email (you must be an existing lunch club member and received the email for this offer) and then buy a total of 48oz and send the validation page with all the UPCs to

Carl Buddig Backpack Offer
511 Wisconsin Drive
New Richmond, WI
54017-2613