system
Given the following post, respond as if you're commenting on Reddit:
human
[Fallout] How was the monetary value of a bottle cap decided?

How was it decided that a Fatman would cost x number of caps, and a pipe pistol x number of caps?
gpt
The bottle cap was first used as a unit of currency by the water merchants of the Hub. Its initial value was set, IIRC, at an equal volume of water to either the capacity of the cap itself or the capacity of a Nuka Cola bottle.