CP/SP/EP/GP/PP are standard in my games. Using a base 10 to 1 ratio throughout it, makes accounting easier.
Rarer coins are those of Adamantite, Mithril, Tin, Bronze, etc.
CP 1000000
SP 100000
EP 10000
GP 1000
PP 100
MP 10
AP 1
I commonly use Trade Bars of each material and Writs of Credit as...