The doubloon is the basic unit of currency in PotBS.
In-game you will see players abbreviating it to db.
The word doubloon (from Spanish doblón, meaning double), meaning a double-sided token coin, often refers to a seven-gram (0.225 troy ounce) gold coin minted in Spain, Mexico, Peru, or Nueva Granada. The term was first used to describe the golden excelente, either because of its value of two ducats, or because of the double portrait of Ferdinand and Isabella. Later, it referred to a coin worth two escudos (0.1905 troy ounce gold), first minted in 1566, during the reign of Philip II of Spain.
In Spain, doubloons were current up to the middle of the 19th century. During the reign of Isabella II of Spain, it was neglected in favour of the real, and finally supplanted by the peseta in 1869. The last Spanish doubloons (showing the denomination as 80 reales (de vellon)) were minted in 1849. After their independence, the former Spanish colonies Mexico, Peru and Nueva Granada also minted doubloons.
Doubloons have also been minted in portuguese colonies, where they went by the name "dobrão", with the same meaning.
In Europe, the doubloon became the model for several other gold coins, including the French Louis d'or, the Italian doppia, the Swiss duplone, the Northern German pistole, and the Prussian Friedrich d'or.
In New Orleans and Mobile, Alabama, doubloons usually made of aluminum have been thrown by Mardi Gras carnival krewes since at least 1960, when the Rex Krewe reportedly first used them.