What type of stamps can be classified as semi postal stamps?

Semi postal stamps are designed to fulfill both postal and charitable purposes. This means that a portion of the sales from these stamps is allocated to support specific causes, such as health, education, or disaster relief initiatives. By purchasing semi postal stamps, buyers not only pay for postage but also contribute to a charitable fund, thereby combining the functionality of traditional postage with a proactive role in supporting societal needs.

The other types of stamps listed do not fit the definition of semi postal stamps. Stamps used solely for local deliveries serve a different purpose, as do international shipping stamps, which are specifically crafted for overseas transportation. Stamps purchased in bulk discounts usually pertain to pricing models rather than any specific functionality related to charitable support. Thus, the distinguishing characteristic of semi postal stamps is their dual role in enabling postal services while simultaneously providing a means to fund charitable activities.