Anecdotally, people in my life used to buy plastic garbage bags and use shopping bags as garbage bags (or dog poop bags) in smaller-sized garbage bins. Also anecdotally, despite the fact that I almost always grocery shop with reusable bags, I still somehow have plenty of plastic bags under my sink at any given time to use in my smaller trash bins. There are plenty of non-grocery places I get plastic bags: CVS, take out meals, Home Depot. These more than fill my need for small plastic garbage bags.