the Fifth Age of Ert
Most of the world’s gold was mined during the First Age. That doesn’t mean there still isn’t gold out there.
In the Vast Empire of Persia, it minted the first Coin: the Gold “Crown”. This coin and the copies of the Era are the standard of all coinage in the the world today.
Also during this time there was the minting of the Silver “Scepter”. However this coin was minted in much smaller quantities in the Viking Kingdom.
Lastly, in Asia there was the Copper “Orb” coin minted. There are more of these than the Scepter but it is also far, far less numerous than the Crown.
These coins are traded at a ratio of 10 for one like standard AD&D. But then there are also numerous local coinage at the copper level and below. These in general are known as either Bronze or Pennies. Most transactions are done at this level. As a GM I don’t track pennies (and don’t ask Players to do so but are welcome do it). But Pennies are the most common of currency. They are traded at at ratio of x10 to the rare Orb coin.
In the Fifth age there has been an introduction of Paper money. But this is still fairly uncommon and local occurrence. Mostly used for large transactions involving banks. they are also “magically” stamped to protect them from counterfeiting.
Purchasing Power: Think of the gold coin as a modern $100 bill. Except you are in the third world waving around a $100 bill where most people earn $1 a day. Also in the Third World food cost about 1/3th as in the states, basic logging about 1/4th and labor about 1/10th the cost.
But modern luxury items still cost just as much in the states. So while a farm laborer makes about 200 pennies (200pp or 2 cp).
a “loosie” cigarette 10pp
a pound of veggies 30pp.
a ten minute “taxi” ride in a rickshaw 15pp
a common room in a flat 60pp
a New Sword 7 gp
a Fancy dinner 6 sp
That sword is 7,000 pp and unattainable by the masses. So even the poorest of adventure armed with weapons and armor is in the middle class.