I've talked to a few "experienced" people about it and in past, they have given away back packs, but I'm bringing one anyway to carry stuff. Just easier to be prepared. If I get a free one, great, but if not, no big.
I think there will be lots of free, small things - cards, small posters, nothing expensive really but it would make sense. I noted Burger King has a booth, so maybe we can pick up the exclusive there? As for the poster tube, probably not a bad idea, but I'll wait and see what I end up with.