I kept the sticker, of course. It has a foil background and a yellow blank back. Note that these have rounded corners. I don't know how many stickers are in a full set here, but I'm assuming that there are 12.
I also saw candy boxes and small chocolate wrappers featuring individual members of the group, but once again I don't have any desire to have them in my collection. Perhaps I'll come across some in a 10-yen box somewhere.
These are all limited-time items, and many of them have already sold out at my local 7-11! But I'm sure they're available through secondary markets, including Yahoo! Auctions.
And I haven't done an "Idol of the Week" post in forever, so I guess you can consider this my return... of sorts.