I wrote a letter to the co-op newsletter suggesting that customers who re-use bags should get a 3 cent rebate off their grocery bill. Personal interest is good for the environment, and that is one of the co-op's goals, in addition to providing low-cost quality food.
The co-op did not implement my idea.
But Safeway was always reading the co-op newsletter. If the co-op put a product on sale, so did Safeway. If the co-op got a store-label version of a product, so did Safeway. Within a few months, Safeway was giving 3 cent refunds to customers who brought in their own grocery bags. Safeway was selling cloth grocery bags. At one point, if a customer saved up $300 worth of grocery receipts, s/he could trade them for a cloth grocery bag.
Now most grocery stores will give customers a rebate for bringing their own bags. And the co-op grocery stores of Berkeley are out of business.
Here's my next campaign -- bring your own plastic box to restaurants to package up your leftovers. Those little boxes cost a dime. Even if the restaurant doesn't give you the dime, you will be helping to save the environment.