This is a beautiful turquoise blue first day cover for a UN 15-Cent Aerogramme from 1972. It is postmarked New York, October 16, with a UN cancel.

Most items under $20 ship in a first-class envelope with collectible stamps and with glassine (for loose stamps) and card stock for protection; more expensive or heavier items may go Ground Advantage or Priority Mail. 

Check out my store for stamps, postal stationery, and covers (first day, space, flight, and more) from the US and worldwide. Most items come from my historian dad’s collection amassed over the course of more than 65 years. He specialized in the US, Nepal, and mountain climbing but collected from all continents.