Global forever stamps are $1.20 at retail, so that's the upper bound on their postage expense and covers all UPU countries[1] (incl DPRK, Syria, Russia, etc).

Global forever stamps are $1.20 at retail, so that's the upper bound on their postage expense and covers all UPU countries[1] (incl DPRK, Syria, Russia, etc). Antartica actually only requires domestic postcard rates ($0.34) as it has a domestic zip code (96598). [1]: http://www.upu.int/en/the-upu/member-countries.html http://www.upu.int/en/the-upu/member-countries.html