Keep on eye on the Mommysavers sample and freebies forum. I have gotten lots of individual snacks mailed to me. I keep them in a container for an on the go snack. (granola bars, chex mix bags, small boxes of cereal, candy bars)
Give your child a baggie and when the snack boxes are down the the bottom have them combine them into a baggie to make thier own snack. Works good with cheez its, cheerios, raisins, crackers, chocolate chips
My dd's love to have cracker sandwiches instead of bread. I just put the peanut butter/jelly/lunch meat/eat salad/whatever in separate containers and then the girls make their own cracker sandwiches as they eat.