Postage stamps are small pieces of paper that postal authorities affix to letters or parcels. The stamps denote certain specified values that indicate the amount of postage paid. Stamps are commonly used to denote the priority of the letter or parcel being sent. One can purchase postage stamps through coils, booklets, self-service kiosk stamp “sheetlets,” and sheets. There are multiple types of postage stamps. Some such types are listed below for further information: Forever stamps These stamps are used to send a letter one way at the existing First-Class Mail Letter rate specified by the United States Postal Service (USPS). This rate remains constant even if the sender’s cost of mailing exceeds one dollar. These stamps are valid for non-profit mailings such as magazines. Also, all forever stamps are good for 1 ounce (about 28 grams), regardless of value. These stamps are also commonly classified as first-class, one-ounce “non-denominated” stamps. Semipostal stamps These regular postage stamps are sold at higher prices than similar, comparable items. Sellers of these stamps earn more money when they sell them. Some profits generated by the sale of these stamps go towards the causes favored by any organization the buyer chooses upon purchasing their semipostal stamps.