Most races have a medium of exchange with which they buy and sell goods with other world as well as among their own people.
The value of a given currency on the interstellar market is usually dependent on the wealth, or perceived wealth of the race that controls it. [1] Not all races poses currency and instead rely on pure barter or a credit system for trade. The Hyach for example consider currency to be vulgar.[2]
Earth Alliance Credits
credit chits accepted by cart vendors on B5
The Earth Alliance uses a credit based system, mostly for book keeping purposes and is exchanged via a computer credit chit that stores the owner's account details and DNA to prevent forgery.[3] Visitors to Earth Alliance territory must usually exchange their native money at a local exchange, assuming it is a recognised currency and are then issued a credit chit that is tied to their EA account. Those who live and work in the Alliance have their salaries paid directing into their credit accounts.[4]
Centauri Ducats
The Centauri Republic economy runs on a hard currency called "Ducats". [5]