In Fallout, what currency is primarily used instead of money?

Bottle caps

Who prophesied the famine during Emperor Claudius’ reign? In which film did Arnold Schwarzenegger first portray the character Conan the Barbarian? In "Street Fighter", which character is known for their stretching limbs attacks? Which musical symbol instructs musicians to gradually play louder? Who was the first person to win an Olympic gymnastics perfect score of 10?