In the times before the Blight, most of the known adopted a common coinage
scheme estabished by Galrathia in order to facilitate trade. This system is
based on powers of 12, with each denomination being worth 12 of the previous
denomination.
One copper bit is the lowest denomination of currency.
One bronze penny is 12 copper bits.
One silver talent is 12 bronze pennies or 144 copper bits.
One gold crown is 12 silver talents, 144 bronze pennies, or 1728 copper bits.
Carrying many coins, especially of lower denominations, may bog you down. You
can change or deposit them in a bank for safe keeping and to lighten your load.