Gadgetscollection via eBay offers the U.S. Shelby Co Military Issue Can Opener 5-Pack, model no. P38-5, for $4.45 with free shipping. (HobbyToolSupply via Amazon charges a few cents more.) That's tied with our mention from two weeks ago and the lowest total price we could find by $7. They're made of stainless steel and each folds into a 1.5" x 5/8" flat piece.