Most Post Offices have a small wire rack display where Priority Mail and Express Mail pre-printed packaging is made available to the public. These displays will usually have a white fiberboard table on top, a chained pen on the table and another wire or plexiglas holder that contains forms such as Delivery Confirmation and Signature Confirmation barcode stickers as well as Express Mail and Customs.
One night, I stepped into the University Park Station Post Office (Denver, CO) to realize that the old wire-frame display had been taken away, leaving no supplies in its wake. The wire display was taken into the locked area near the retail windows (it would later disappear for good), and no boxes or envelopes were available for use.
The next day, this little thing showed up next to the APC. It's shaped like a USPS outside collection box, only bigger and made of cardboard and aluminum. Inside lies a stack of neatly arranged Priority Mail and Express Mail packaging. There are no customs or Delivery Confirmation forms available, but I guess the intention is for customers to mail these boxes out using the nearby APC, which prints its own special barcode labels, takes your postage payments via credit card and doesn't do international parcels.