Unlike Official stamps and military stamps, Franchise stamps are issued to nongovernmental organizations or private citizens. These stamps allow the sender to use mailing service without paying postage. Franchise stamps were used frequently by Portugal. They were issued for Red Cross Society, civilian rifle clubs, the Geographical Society of Lisbon, and the National Aid Society for Consumptives.
Civilian rifle club franchise non-denominated stamps were issued by Portugal from 1899 to 1910. These were colour-coded depending on the year of issue. Each stamp had validity for only one year.
These stamps are popular among Portugal stamp collectors, militaria topical collectors, and collectors of other classic stamps. A set of 12 such stamps has an officially listed market value of $37.45 in unused hinged condition as well as used condition. Several unused stamps exist without gum and have a lower market value.
Image Courtesy: 2018 Scott Standard Postage Stamp Catalogue