I almost have enough to build my dirt - bag (Lol) hut for meditation. I needed 300 and have been getting donations from my SIL who has pigs, fowl and rabbits. Almost there... can't wait!
We're saving ours for a project that Mother Earth News talked about. You fill them with dirt and build a round (or other shape) igloo style building. Can be used for many things, we would use our first one for storage. It takes about 300 bags to get a good sized building, but we get them from...