Currency in Space

Something I should have spoken about at the beginning of the crew area, especially when I spoke of the ship store and vending machines was what currency your ship has. Most futuristic shows, movies, and books suggest that people will pay by a chip in their hand or a version of the modern credit card that they merely hand to the vendor and the money is automatically taken out of their account. The US Navy uses a similar concept on their ships where cash is rarely used and no longer necessary. Another idea is in the Star Trek series where money seems to have no use inside parts the Federation but they use Lithium as cash outside the Federation. However you decide to handle money on ship you can be sure that it will come up at least once in your story, unless your culture is very non-materialistic or never trades with other cultures.