Bottle cap Bottle caps , also referred to as caps for short , are the standard currency in " Fallout " , " Fallout 2 " , " Fallout 3 " , " " , " Fallout 4 " , " Fallout Shelter " , and " " . Background . < section begin = " background " / > In New California , the relative scarcity of bottle caps made them a perfect currency for Hub merchants to adopt in the 22nd century , leading to the nickname " Hubbucks " and " Hubscript . " Backed by the value of water , the Hub merchants supported bottle caps because the technology to manufacture them and paint their surfaces had been mostly lost in the Great War , which limited any counterfeiting efforts . Secondly , there are a limited number of bottle caps , which preserve their value against inflation to some degree . For similar reasons the East Coast merchants also recognize bottle caps as a currency , although who backs them and guarantees their value is unknown . While becoming the standard currency for Hub merchants in the 22nd century , by the mid - 23rd century bottle caps were replaced by New California Republic ( NCR ) dollars , which were backed by gold . Caps would once again become a regularly - used currency after the destruction of NCR ' s gold reserves by the Brotherhood of Steel destabilized the value of the dollar . By the late - 23rd century , the NCR ' s tenuous grip on New California , the presence of Caesar ' s Legion ( who have their own currency ) , and the low value of the now water - backed NCR dollar caused bottle caps to re - emerge as the standard currency of the Mojave Wasteland in 2281 . Nevertheless , NCR and Legion currency are both considered legal tender by the various caravan companies and on the New Vegas Strip . Mojave merchants also accept nonstandard variants , such as Sunset Sarsaparilla bottle caps . < section end = " background " / > However , based on the relative prices of items on the East Coast and West Coast , the bottle cap currency is used in larger amounts in the former . Variants . Nuka - Cola bottle cap . 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 games ; in " " , they don ' t appear to be worth as much as they are in " Fallout 3 " . Counterfeit Nuka - Cola bottle cap . Physically they appear identical to standard Nuka - Cola bottle caps and are presumably intended to be used for trading in place of actual bottle caps . They are produced by unknown persons , have no trade value , and cannot be used for any monetary purpose . Sunset Sarsaparilla bottle cap . This nonstandard variant , taken off Sunset Sarsaparilla bottles , is used in the Mojave Wasteland alongside Nuka - Cola caps . Sunset Sarsaparilla star bottle cap . A rare variant of the Sunset Sarsaparilla bottle cap , featuring a blue star on the underside of the cap . These can be traded in to at the Sunset Sarsaparilla headquarters for a reward . Bawls bottle cap . is a real - world energy drink with a guarana flavor that replaced Nuka - Cola as the main post - nuclear soft drink of choice in " " . This special type of bottle cap is valued as 100 times that of a Nuka - Cola bottle cap .