I'm not sure what's on your school supply list, but one thing that we always put on ours are boxes of tissues. Some years I've got cabinets full of tissue boxes and other years my students fly through those tissues!
Empty tissue boxes are great for those no-peak grabbing boxes.
For example at Calendar I have a box of numbers or domino cards for different parts of my calendar lesson. I just dump my cards in the box and the kids can reach in without looking to pull out cards without making a mess. The box lasts a lot longer than the plastic sandwich bags I used to use. Students would always drop those or rip them for some reason, leaving an annoying mess.
You can also use the box as a place to turn in various activities like anonymous compliments, a tattle tale box, or a name drawing box for prizes (students can put their names in the box for each time they earn a chance for the prize). The possibilities are endless!
Some of these tissue boxes the kids bring in are cute with little monsters or cartoon themes, but if they're plain or you have your own theme going on tissue boxes are easy to recover and decorate as well. =)
Obviously I don't keep ALL our empty tissue boxes thereby becoming a pack rat, but I at least get to reuse some of these empty boxes!