REDUCE, REUSE, RECYCLE
When I first review the list each year, I pull out all the old school supplies I put away for the summer. Before I go out and buy anything new, I check to see what is in reusable condition from the previous year. Plastic folders have stickers removed, crayons are put in a new container to reuse, markers are reused as long as they still work, notebooks have used paper torn out of them if they are less than 1/4-1/3 used. Scissors, erasers, and pencil pouches, all reused from the previous year (unless your child lets crayons get hot and melt in said pencil pouch... ya, that totally happened two years ago. Sadly, that pouch wasn't saveable.) Bonus if your child comes home with pencils in good shape! Those get resharpened and reused as well!
Backpacks, lunch boxes, reusable lunch containers, stainless steel water bottles, all are reused from the previous year.
Here are some of my favorite reusable items!
Reusable snack/sandwich bags - From Huckleberry Creek
Collapsable silicone food storage containers - From Mighty Nest
Stainless Steel containers with silicone lids - From Eco Lunch Boxes
Any items that cannot be reused, is recycled if possible. Paper folders have the progs removed and paper notebooks are either composted or recycled. Old crayons of ours get tossed in a tub. Once I collect enough, the labels are removed and they are either melted down into new crayons or the melted wax is poured over dryer lint in a cardboard egg carton to create fire starters!