So I got this idea from another persons instructable and decided to do one of my own. His is here http://www.instructables.com/id/Pallet-shelves/ . I liked his but had never made an instructable and decided to give it a try. I needed to organize the camping and boy scout stuff that basically accumulates in my basement so these seemed like a great option. At $8 Each these are excellent.
FIrst off, you need to find wooden pallets and free is best! I got mine from a local roofing company. most of the big name stores wont give theirs away or use the new plastic ones that they have to send back on their trucks. Also you need a box of 3 or 4 inch screws and 4 six foot 2x4's per shelving unit.