Three coins circulate in the dungeon, and they are only ever copper
counted three ways:
1 gold = 10 silver = 1,000 copper
1 silver = 100 copper
Everything you earn is banked in copper and shown to you in the
highest denomination that fits, so a purse of 1,250 copper reads as
'1 gold, 2 silver, 50 copper'. Nothing is lost in the conversion —
there is no money-changer, no spread, and no fee.
Where the coins show up:
gold Aliases: money, wealth, coins, copper. Your purse,
plus this exchange rate.
hud The same figure, alongside the rest of your profile.
%c The purse code for the status prompt — see
'help prompt'.
Where they go: shop-keepers price in the same breakdown ('buy' and
'sell' — see 'help shop'), so a jerkin at 8 silver is 800 copper, and
a corpse that pays 40 copper is a twentieth of it. Boxes, corpses, and
the sacrifice bonus are where copper comes from.