I notice on the <a href="https://rover.ebay.com/rover/1/711-1751-2978-71/1?AID=5463217&PID=2585675&mpre=http%3A%2F%2Fwww.eb ay.com%2F">Ebay front page</a> (middle, right) that Ebay members can get free boxes. This is a program for Ebay sellers.

eBay and the U.S. Postal Service are happy to offer you FREE co-branded shipping boxes for Priority Mail® and Priority Mail Flat Rate Service. These boxes will be delivered directly to your home at no cost to you.

Full details here.