The U.S. Postal Service began issuing “Forever Stamps” in 2007 and the face value is always worth the current first-class postage price for one ounce. New stamps sell for $0.66 each as of August 18, 2023.  Forever Stamps purchased before a postage rate increase are worth the new rate even though you spent less. So, if you bought the first-ever Liberty Bell forever stamp for $0.41, it now has a face value of $0.66 and will continue to match future postage rates.