The five types of metal coin mentioned in your HMb book (p129) are all represented in the currency of the Kingdom of Aneth. Below is detailed each coin type along with it’s colloquial appellation (colloq.), common abbreviation (abbr.) and silver piece value (spv).
Bronze Pieces | colloq. Bits | abbr. bp | spv 1/100
The lowest denomination coin in the kingdom is the bronze piece, minted by the nobility to expedite the daily business of the peasants under their protection. Bits are the only Anethian coins not to carry a likeness of the king on one face; the nobles minting them may choose whatever images they deem appropriate for both sides of the coin, though most insist on their own face.
Copper Pieces | colloq. Groats | abbr. cp | spv 1/10
The most common Anethian coin in circulation is the copper groat. It is the smallest denomination of coin issued by the crown, although the vast majority of groats are minted by nobles since the king has little use for such low value currency. Like bronze bits, copper pieces are used for many day-to-day purchases.
Silver Pieces | colloq. Shillings | abbr. sp | spv 1
More common amongst the Anethian middle classes is the silver shilling, minted by the crown and nobles alike. Permission is not required for nobles to issue silver coinage but strict annual records must be submitted to the crown accounting for local currency. The silver piece is often the highest denomination of coin most people will ever see.
Gold Pieces | colloq. Drakes | abbr. gp | spv 10
Most gold drakes are minted by the crown, but with royal permission Anethian nobles may issue their own gold coins. Permission is rarely refused however, since the ability to produce high value coins locally helps keep the kingdom’s economy running smoothly. Plus of course it is far easier for the nobles to deliver their taxes and tributes in smaller numbers of higher denomination coins, than having to cart chests of silver, copper and bronze coins to the capital.
Platinum Pieces | colloq. Crowns | abbr. pp | spv 100
Only the king has the authority to issue platinum coins, a fact reflected in their common nickname ‘crowns’. These rare coins tend only to be used by the upper classes as only they can afford such goods and services that demand so high a price. It is said that the king occasionally travels his realm incognito, and that any vassal who should recognise and challenge him will be rewarded with a platinum coin (a small fortune to a peasant).
Seerstone Moneylenders & Banking Services
As one might expect of a medieval feudal town, Seerstone high street is not overly blessed with banking institutions eager for your characters patronage. Indeed there is only one such establishment that openly offers any kind of financial services to the independently wealthy within the jurisdiction of the Lord Seerstone, and that is the office of his tax collector. Loans and savings facilities are offered at various rates of interest, dependent on the petitioners status. A money changing service is also available at a flat rate of 5% of the face value of the currency to be changed; large amounts however may take several days (or even weeks) if the required coinage is not readily available.