Both the major countries have their own systems of currency, which can be easily exchanged to one or the other at any bank. The settled floating islands have their own types of currency as well, which might be a little harder to exchange, depending on if you're in a city.
Ivona prints their own currency, whose value fluctuates based on what's in Ivona's treasuries and what the economy does to it. One franc equals to 100 centimes, and has little value based on the materials it's made of itself.
Vohemar basically uses a glorified bartering system. They use precious gems and metals as currency, based directly on their actual worth. One dubloon is equal to 100 bits, and though Vohemar melts the metal into coins and stamps them, the coins can have different weights depending on the metal they're made of. It's a little harder to use gems for currency, and thus rarer, but it's basically the same guidelines going by worth.
Currently, one franc is roughly equal to one dubloon.