About 20 years ago, one of my aunts taught me to re-use the liners that cereal comes in inside their boxes. She recommended I use them instead of wax paper. Since then, I have had the same box of wax paper sitting on the shelf in case I need it. But, I have used mostly the inserts. I rinse them, let them dry and then store them for use later.
This year, I discovered that being they put so much glue on them now it is almost impossible to pull them apart, that I have started using them whole as freezer bags! I use the twist ties to close them or put it into already used(clean) plastic bags that I don't want the food to touch, but gives another layer of freshness to the food!
As for plastic bags, I use them again and again ... according to how clean they are. Then when I don't want to use them any more for food, I use them for scraps before throwing the scraps into the trash.
Then, of course, the shopping bags are used for trash cans. I do have all those reusable bags I bought, but I rarely remember to take them into the store!