A long time ago back in Mayan civilization Cacao beans were used as currency (amongst other things).
Cacao was valuable because it was considered precious and scares, there were difficulties involved in growing and producing cacao beans - in particular, its low yield made it an expensive commodity.
Cacao is one of the best examples among the more primitive means of payment. But because it could not fulfill all the functions of a monetary instrument, It served more as a means of exchange but not as a standard of value. Cocoa beans were divided up at will and used in negotiations.
Because Cacao is delicious to eat, those who had cocoa beans of their own were more tempted to eat them than plant them in the ground.
Like any well-trusted currency, cocoa beans were also the target of counterfeiting in various forms. For instance, forgers emptied the precious bean and then filled it up with mud to give it a weight equivalent to one cocoa bean. Painting clay to look like a cacao bean was another form of counterfeiting.
Cocoa was without a doubt the main barter currency of the Empire, of such importance that its value was fixed officially in 1555 by a decree that stipulated that one Spanish real was worth 140 cocoa beans. According to various websites the value of other items where; 100 beans for a slave, the services of a prostitute cost 7 - 10 beans, and a turkey cost 20 beans. The use of cocoa money spread to other countries lasted until the beginning of the 19th century.
To read more on the value of cocoa visit my source nbbmuseum