I am submitting this tip from the nurses at our clinic who use rolling carts, but had only one small drawer on top to store all their items. They needed more storage and they came up with the idea of adding one of the plastic 3 drawer filing cabinets to their rolling cart. They just hold it on with bungie cords in the back. Now they have much more room, and it is not too heavy to roll around and it is very inexpensive. About $11.00 on sale for the plastic file cabinet. I thought this was a very clever idea.