I found what I was looking for at another dollar store: I was able to get enough pencil cases for the boys and the girls. I've stuffed them with candy and trinkets (pencils, erasers, stickers, etc.).
I like the contents to be useful, and as a parent any time I can promote writing or drawing I try my best. With that in mind, I don't think I've ever done a goodie bag that didn't include a pencil/pen/crayon of some kind.
One year for goodie bags I gave each child a pad of construction paper and a small box of crayons. An added bonus to this approach is that if you have leftovers (I usually make a few extra bags), then you have usable craft supplies for your own kids.