I've noticed that there always seems to be something on the box, like, mail in the upc and we'll give you this or that. Someone told me the smaller boxes about a month back had itunes gift cards in select boxes (and she had one with a 10.00 card!)
It's never been anything I wanted though. Until today. I was putting stuff away and I saw that with 5 vouchers on select boxes, you can get a free movie ticket for the new Star Trek movie. We'll I bought 6 poptarts, all with the vouchers, so I thought I'd send them in and see I get a movie pass. When I cut out the form inside the box, its says its good for Star Trek or ANY movie at a participating location. So I got 2 free movie tickets when I bought them, and now I'm going to get 1 in the mail?? Sweet!
Moral of the story is. Check your boxes, You never know!