Plastic Bags cost $0.00 (typically). They&#x27;re handed away for free from Grocery stores. Cleaning up Plastic Bag Pollution costs more than $0.<p>This market failure is called an externality. The people who use Plastic Bags don&#x27;t pay for Plastic Bag pollution. I mean, its a very small externality in the great scope of things, so I don&#x27;t really give much of a care. Maybe about... $0.05, the current tax on plastic bags in my area to take care of this externality.<p>But its still clearly a market failure (specifically an externality). <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Externality" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Externality</a><p>A plastic bag tax shifts the externality and fixes the market failure. Now either the grocery store or the consumer who uses the plastic bags have to pay for the pollution they cause.<p>The reason why San Francisco is dumb is because they go off the rails and turn into a nanny state. I agree with San Fran that Plastic Bags are a nuisance and that somebody needs to pay for the cleanup effort. But the ban goes too far.<p>On the other hand, a minor-bag tax levied by the local municipality (who pays for the road-cleanup crews who pick up the plastic bags) makes 100% sense. That&#x27;s the purpose of taxes: to force people who otherwise aren&#x27;t paying for something... to pay for a service that they&#x27;re taking advantage of. Taxes are a lovely mechanism for solving market failures that involve externalities.