I save ALL the bags that I buy containing soil or mulch or whatever. I have a municipal site close to me where I can get all the mulch and compost I want, so I use them to transport that, and also for yard waste, leaf collection, plant soaking, plant sharing/'transport, everything. At the end of each season I hose them out, let them air dry, bundle them up, and store them in yet another reused bag! Once they are sufficiently full of holes, I finally recycle them.