postage (n.)

1580s, "the sending of mail by post;" 1650s as "rate or charge on letters or other articles conveyed, cost of sending something by mail," from post (n.3) + -age. Postage stamp is attested from 1840 for "official mark or stamp affixed or embossed as evidence of payment of postage." The things themselves were noted as being collected in albums by 1862. As the type of something very small by 1962.