I just bought used industrial shelving for my shop. Don't have it installed yet as I am still waiting for some of the liner and electical to be installed.
The heavy shelving cost $70 per unit, 4 feet deep and 8 feet long with three shelves per unit. Choice of heights was 7-10 feet high, same price.
I also got some 48 inch high and will shorten the uprights with a cutoff say to reduce them to workbench height. They only have 2 shelves but only cost $40 a unit. It all came from a Wal-Mart store.
The prices are 1/5, or less, than the same quality new shelving plus there was no shipping costs, a sizable amount on some as heavy and bulky as these shelves.
Around here it isn't the mice that chew up tractor wiring and such. It is chipmunks. Their favorite color is blue.