What is the primary purpose of semi-postal stamps?

The primary purpose of semi-postal stamps is fundraising. These stamps are sold at a price higher than that of regular postage stamps, with the additional funds specifically earmarked for particular causes, such as health issues, disaster relief, or historic preservation. This unique approach allows the postal service to support various charitable initiatives while still providing a means for postage.

The additional value collected above the standard postage cost is allocated to designated programs or organizations. This system empowers the public to contribute to important social and charitable causes through their everyday mailing needs, enhancing the role of the postal service as a community resource beyond just mail delivery.