USPS Global Forever Stamps - 20 Stamps (20) Global Forever Stamps (either one sheet of 20, or two sheets of 10) Global Forever stamp can be used to mail a one-ounce letter to any country to which First-Class Mail International service is available Valid for first class postage at current rate (1.15 per stamp as of 2017) May include any variety of Global Forever stamp including Succulent, Moon, Sea Surface, Silver Bells, Evergreens or Earth.