Acme reusable grocery bag, $5.95 That feeling of moral superiority, priceless.
Une femme's green intentions are good. Last year, we bought several of those large reusable grocery bags sold at markets ($1 each, conveniently displayed right next to the checkout line) to carry our goodies home. But then they remained behind in the closet where they were stashed after we put our groceries away, or in the trunk of my car where, intentions aside, I invariably forgot them until I was at the register with my cartful of food halfway rung up.
Before our Paris trip I ordered a couple of these Acme bags online, as we'd planned to do some shopping at outdoor markets. I didn't use them much in Paris, but since I've been home have found them indispensable. They weigh nothing, fold up neatly into a self-pocket, a size that's easily accommodated in my purse where they are always available. When they ask "paper or plastic?" you can chirpily reply, "neither, I have my own" and do a small part for the environment.