The purpose is to hold all of those little things that will get lost in a desk, scissors, pencils, crayons (after the box breaks), glue, ...Originally Posted by Tirlittan
Some teachers are specific on the size they want because of the size of the desk.
There are cardboard ones and plastic ones specifically called school boxes, but the hinges usually crack and break. Instead I bought a small rubbermaid type container the same size. It was much more durable and lasted for several years.
About the crayon and marker boxes breaking. I usually tape them up brand new and then they last the year.