Non-denominated postage is postage intended to meet a certain rate that retains full validity for that intended postage rate even after the rate is increased. The consumer facing name from the United States Postal Service is known as the Forever Stamp.
It was in 2006 that the United States Postal Service applied for permission to issue a stamp termed the forever stamp, referencing the non-denominated stamps available in the United Kingdom.
On March 26, 2007, the United States Postal Service unveiled the first forever stamp, which went on sale April 12, 2007, for 41¢. This initial design is called ‘Liberty Bell’ and was labeled with the text “USA FIRST-CLASS FOREVER.”
This initial batch of Forever Stamps ran until October 21, 2010 in which a second design was announced.
In 2011, all first-class stamps were made to be forever stamps, forever modifying the USPS stamping denomination offering and placing the Forever Stamp in the apt permanent product offering for postal customers.