Plastic bags are manufactured from crude oil at the rate of 12 million barrels of oil per year at present!  So change a bad habit.

• Decline a plastic bag for one or two items, especially when they come in a bag, box or bottle already (like bread, soft drinks, or milk for instance).  And make a point of suggesting to the register clerk that he or she ask, “Do you need a bag for this one item?”  Lot’s of clerks are aware of the problem and just need a little support in changing their bad habits too.
• Reuse your plastic bags.  If you learn to fold them, first the long way to let out the air, then roll them around your palm to make a small flat package, then you can tuck one in your pocket with your handkerchief to have handy when you need it. My dad taught me that trick, and that was way before the current climate crisis!
• Carry a reusable cloth bag with you. The can be bought online from various great websites like the Tibetan Nuns Project (supporting these refugees), same product from The Hunger Site, or from The Rainforest Site.