All your children own is out / Upon the floor, or bed, no doubt / But if that mess you'd rather rout / Try some of this stuff by Sprout / And peace will reign in the valley.
Sprout official site
Those are some expensive cardboard boxes!
Cardboard? For kids?
If you have an Ikea nearby, I recommend Expedit - you can get an 8 unit shelf for $70, with sturdy fabric boxes for $5 each.