Currency

Several different types of Currency are used in the world's various economies.

The Seven Kingdoms of Westeros have a uniform system of coinage based on the "Gold Dragon" coin. The different cities and nations across the Narrow Sea on Essos use their own various local currencies.

The Seven Kingdoms
The coinage used in the Seven Kingdoms is based on the Gold Dragon, and its various denominations, chief of which are the Silver Stag and Copper Penny. As their names suggest they are made of these precious metals, and are based on the inherent value of the metal (the "gold standard") not theoretical value (not a "fiat currency", based on abstract banknotes).

That being said, sometimes possession is an abstract concept. Thus someone being paid thousands of Gold Dragon coins will not have to physically carry them around, but will be presented with official financial documents declaring the transaction (much as a knight might find it difficult to carry around on his back a castle he has been granted, but can carry around a sealed charter as proof of the land grant). Still, even large sums used in accounting - ranging into the tens of thousands of Gold Dragons - are supposed to represent physical gold coin reserves.

Reflecting real-life medieval practice, the currency of the Seven Kingdoms is not based on a decimal system, but grew haphazardly out of many centuries of rival coinage systems becoming integrated, so the exchange rate between different denominations reflects tradition and not abstract sense. Each of the original independent "Seven Kingdoms" minted their own money, but the coinage system was unified under the Targaryen dynasty after the War of Conquest 300 years ago. The Targaryen Kings did not completely "nationalize" the minting of coins, as private mints also exist, but coinage is primarily minted by the kingship and is certainly regulated by it.

The denominations most commonly encountered are, in descending order:


 * Gold Dragons - equal to 210 Silver Stags, or 11,760 Copper Pennies (56 X 210 = 11,760).
 * Silver Stags - equal to 56 Copper Pennies
 * Copper Pennies - also commonly encountered in the "Halfpenny" coin worth half a Copper Penny, and the "Copper Star" which is worth 8 normal Copper Pennies.

There are a few other regional coins worth different combinations that might be encountered from time to time, (a "Groat" equals 4 Copper Pennies, etc.) but these three are the most common.

Barter is, of course, still common on an everyday level.

Examples within the TV series

 * When he became Hand of the King to Robert Baratheon, Eddard Stark was shocked to learn from Lord Petyr Baelish that the Iron Throne was an astonishing 6 million Gold Dragons in debt. Approximately half of this debt was to House Lannister, the wealthiest noble house in Westeros due to the many gold mines they control in the Westerlands.
 * Robert Baratheon ordered a Tournament to celebrate the appointment of Ned Stark as Hand of the King. The prize money offered included 40,000 Gold Dragons to the winner of the joust; 20,000 to the runner-up of the joust; 20,000 to the best archer; and 20,000 to the winner of the combat with swords and clubs. Ned Stark considered the total prize money of 100,000 Gold Dragons to be an extravagance the crown could not afford, but Robert ordered it anyway.
 * During the tournament, Lord Baelish wagered Renly Baratheon 100 Gold Dragons that Ser Gregor Clegane would win against Ser Loras Tyrell in the joust. Baelish mused that 100 Gold Dragons could buy a dozen barrels of expensive Dornish wine.

Beyond the Wall
The Wildlings living north of The Wall have a hardscrabble, survival-based economy, with little settled agriculture. As a result, Wildling villages that the Night's Watch encounters are more interested in directly useful things that they can barter for, such as weapons, furs, or fine wines, and usually not coinage, which has little inherent use to them.

Essos
There are many different systems of currency in the eastern continent, particularly in the merchant city-states known as the Nine Free Cities.

Unlike Westeros, much of the economy of the cultures in Essos is based on slavery. While feudal serfdom is the social norm in Westeros, the laws of the Seven Kingdoms specifically outlaw slavery there. Payment in slaves is frequently used as a form of barter in Essos.

The Nine Free Cities
Due to their location on the western end of Essos, they conduct brisk trade with the Seven Kingdoms, using fleets of merchant ships.

The practice of slavery varies between the different Free Cities. Volantis, the largest and most populous of the Free Cities, is also located closest to Slaver's Bay to the east, and it is deeply involved in the slave trade. On the other extreme Braavos, the most powerful of the Free Cities, was founded centuries ago by refugees fleeing slavery under the old Valyrian Freehold, and thus abhors slavery. Generally, Braavos tries to pressure those other Free Cities under it economic and political influence to outlaw slavery as well. It was due to this pressure from Braavos that Pentos nominally outlawed slavery a century ago, though in practice, wealthy and powerful merchants in Pentos such as Illyrio Mopatis flout this agreement and keep slaves anyway. Thus the level of involvement in the slave trade varies from one of the Free Cities to the next.

Dothraki
The Dothraki are said to "not believe in money", instead taking what they want through raiding. The two resources they actually have on the plains of the Dothraki Sea are miles upon miles of grass, and horses. What material wealth or precious objects they possess have been acquired through raiding surrounding nations such as the Free Cities, Slaver's Bay, or Lhazar, or raiding other Dothraki hordes to take their plunder.

The Dothraki do not so much function on the barter system, as they use the honor system: they frown upon "trade" but honor the exchange of gifts, such as tribute. Long ago the Free Cities decided that it was often less destructive to just give the Dothraki massive tributes in gold, finished products, and slaves, than to try to fight them off (though a Dothraki horde might still attack if they find the tribute insufficient, or if they just haven't had a good fight in a while). The Dothraki will not reciprocate these "gifts" on an immediate quid pro quo trade system. However, they will as a rule keep their word to eventually give a gift which they have promised, though they will do it in their own time.

In practice, if a Dothraki horde has a particular need for a resource that it cannot obtain through direct raiding, i.e. new armor and weapons, they will resort to actual "barter" by trading slaves they have captured in return for finished products from the Free Cities or Slaver's Bay.

Slaver's Bay
As their name implies, the city-states of Slaver's Bay are the heart of the international slave trade. Meereen, Yunkai, and Astapor are descended from the empire of Old Ghis in much the same way that the Free Cities are descended from the old Valyrian Freehold. While some of the Free Cities are economically engaged in slavery, and some like Volantis are heavily reliant upon it, the entire social structure and economy of Slaver's Bay is utterly based on slave labor.

Qarth
Qarth is a major trading hub located more or less in the center of the world, between north and south, east and west, next to the Straights of Qarth through which all east-west ocean traffic must pass. In practice, Qarth is the furthest east on the continent of Essos that merchants from Westeros have been known to travel, and is thus at the extreme east of the mapped world to men in Westeros (Asshai and the Shadow Lands are located further east, but they are half-legendy to men in the Seven Kingdoms). They are also heavily involved in the slave trade.

Banking
Each of the Nine Free Cities has its own bank, for depositing and lending money. The largest bank by far is the Iron Bank of Braavos, which is as large and wealthy as the banks of all the other eight put together.

In the Seven Kingdoms, there is no particular cultural or religious rule against moneylending. Indeed, the Faith of the Seven has been known to lend money to the kingship. Thus, by the time of King Robert Baratheon, the crown owes a vast amount of accrued debt which was lent to it, mostly by House Lannister, the wealthiest noble landholders on the continent.

Robert Baratheon's massive public debts, largely the result of his own inept financial leadership, totals approximately 6 million Gold Dragons. This debt is divided roughly evenly between 3 million owed to House Lannister, and 3 million owed to the Iron Bank of Braavos.

When King Joffrey succeeded Robert, backed by his mother Cersei and grandfather Tywin Lannister, House Lannister was really attempting to found a new dynasty and supplant House Baratheon. A problem House Lannister encounters once Joffrey is in power is that essentially, half of the 6 million Gold Dragon debt was owed to themselves, and with Robert dead he can't pay Tywin back. This does not erase the mounting war debt to the Iron Bank of Braavos, particularly given that most of the realm (beyond the Crownlands, Westerlands, and a narrow strip of the southern Riverlands) does not ackowledge Joffrey's rule.

In the Books
The books contain many more examples of different kinds of coins and the relative price of different purchases.

A point made in the books is that the crown of Seven Kingdoms actually was not in debt immediately after Robert's Rebellion. While there had been some war debts (King's Landing had to be extensively repaired after its sack, etc.), the Mad King had been hording gold for so long that such expenses were paid off. Tywin Lannister even remarks that the gross income of the crown has increased to something on the order of ten times what it was under the Mad King, due to various improvements in administration and an improving economy during the long summer years. Thus it is all the more shocking to Eddard Stark when he is informed that the crown is 6 million Gold Dragons in debt, highlighting just how much Robert Baratheon was beggaring the realm with his many expensive jousts. Indeed, Tyrion Lannister is skeptical that even Robert's expensive tournaments and overall bad management could have produced such massive debts given the strong gross income levels, leading him to suspect that Littlefinger has been embezzling massive amounts of money from the treasury.