Make free shelves from big empty boxes.

Light Duty shelves.

Strong enough for books and most things.

Heavy Duty shelves.

Strong enough to stand on. For the actual shelves, use scrap wood or .625 thick partial board shelving.

1 Set big empty box on floor and draw cut lines.

2 Cut and fold.

3 Insert wood shelves.

4 Nail.

5 Stand up and fill.