Caps, also referred to as bottle caps or stylized as bottlecaps, are a miscellaneous item in Fallout 76. Caps are widely used as currency throughout the post-War United States, including Appalachia. Caps can come from certain drinks, such as Nuka-Cola, beer and other malt beverages.
Farming Caps Stashes is the most efficient way to get a lot of Caps in Fallout 76. With Bottle Collector Perk you can get an average of 70-80 Caps per Stash and knowing the exact spots where Stashes are found, can make you nearly 1000 Caps in 10 minutes. The only downside to it is the number of players already farming Stashes on most servers.