Except that rate wouldn't be available at your local post office. The $2.02 rate referenced is only available to an eligible business meeting many requirements to achieve that rate: https://ribbs.usps.gov/shipproductsservices/documents/tech_g...

If NPR was looking to ask the "average" business what it would take to fulfill a single order, they likely got a good answer. And the shipper may have been overestimating final shipping weight if done on the fly.