If you’re at the supermarket and realise you,ve forgot your shopping bags DONT be buying the stores own bags especially if you have a trolley full it could cost you a small fortune just on carrier bags ESP when you already have them at home , pop over to the household isle and buy a roll of white bags, some as little as 69c for a pack of 10/20 etc, put those through the till first then open them and add your shopping into them, once home you can reuse them in your household bins etc