Fallout world has different currency in different areas. In Fallout 76, Bottlecaps are the primary currency throughout the post-War United States. You can obtain Bottle Caps from certain drinks, such as Nuka-Cola, beer, and other malt beverages. Appalachia serves as the game-world of Fallout 76. Bottlecaps are used as currency in Appalachia. It can be found pretty much anywhere in Appalachia, in varying amounts.
Bottle caps seal the opening of a bottle and are typically colorfully decorated with the logo of the brand of beverage. Plastic caps are used for plastic bottles, and metal with plastic backing is used for glass. Standard Nuka-Cola bottle caps featuring 21 crimps and ridges, used as the basic form of currency throughout many of the American wastes. Their value differs throughout the game.