Money in the world is all coins. Minted from precious metals with accepted standard weights and measures. There are eight bits to a round, and a thousand rounds to a hundredweight. The relative value of rounds, sometimes called "pieces" and bits are based on the value of the metal from which it is produced. The metals normally used for coin, in descending order of value, are gold, silver, copper, and iron; iron has ceased being accepted as legal tender in some areas, including Ethshar of the Spices. Officially, a gold round is worth 10 silver rounds, each of which are in turn worth 10 copper rounds, while each copper round is worth 10 iron rounds. The actual exchange rates aren't always exact, however, as scarcity drives the value of metals up and down relative to one another. At the extreme, because it is generally no longer legal coinage, iron tends towards 12-15 per copper.
The standard rate of transaction is in copper. Bits and rounds that don't have a specified type are always assumed to be copper.
Originally bits were wedge-shaped, rather than round, but by the 53rd century they’d gone to being either round or hexagonal. Rounds, of course, are round, but are no longer eight times the size of a bit — instead they’re much thicker, so as to still have eight times the mass while only being maybe a time and a third the diameter.
Sometimes industrious, and less than scrupulous, individuals will shave or clip coins. This reduces the coin's value marginally and allows the scammer to collect the shavings to produce their own coins.
A meal at an inn generally runs a copper piece with water or a silver piece with wine. Brandy or oushka runs two coppers a drink or a silver piece for a bottle.
1 copper bit is worth around $3 - $4 equivalent. This gives a reasonably large value for the smallest coin in circulation.
A full bottle of dragon's blood will run around 6 rounds of gold.