I use those 10p bags for life and carry them from shop to shop. They flatten down well and you can get a couple in your handbag. When they get too shabby the shops (Waitrose or M&S) just give you a new one.
I'd never buy a Disney carrier bag. I detest the Disney corporation. It turns people into morons. (With all due repect to you lou). A cousin of mine took his three children (aged 14, 12 and 2) to Disney Paris. They spent a whole five days in Paris INSIDE the Disney park. They never even went to see the Eiffel Tower. They go to fabulous holiday destinations and spend the whole time inside the resorts eating pizza and egg and chips. They never go and explore the local culture or go and see great cities, buildings, galleries or anything. I'm embarrassed to be related to him at times and, once again, I have to say these people bring out the snob in me.