These are impossible to find even in Sweden (I've only seen 2 for sale for the last 20+ years), most likely cause they were bought by kids and they used them when sending letters, in school books etc. The sheet measures 274 x 206 mm / 10,8 x 8,1. The item "KISS Stamps from 1980 by Swedish POSTER Magazine SUPER RARE! Sweden Full set" is in sale since Friday, January 1, 2021.
This item is in the category "Entertainment Memorabilia\Music Memorabilia\Rock & Pop\Artists K\Kiss\Other Kiss Memorabilia". The seller is "hellfire-club" and is located in Sundsbruk, Sundsvall. This item can be shipped worldwide.