My local target was clearancing out some closet accessories.
I picked up a 2-pack of suit-bags for $4.05. They aren't anything fancy, but they are breathable and cheap. They also had full length bags for the same price (but just a one-pack).
I think I will go back and pick up another set. They aren't nice cotton canvas (its a synthetic fabric on one side and PEVA on the other) but for $2 a piece, they are hundreds of times better than dry cleaning bags or the kind of bag they give you at a department store.