Where can I donate as-new/good condition school supplies?

Often every school year I end up buying one too many notebooks that I need or figure that my backpack/pencil case cant fit the amount of materials I end up having that year, so I have a couple of extra pencil cases/backpacks sitting around that are like new or barely even scratched. Where can I donate these and other stationary that is barely used or opened? I only throw things out if they have a huge hole or damage that makes it unusable/unfixable.