Being the common currency, Credits are primarily used throughout the game and can be earned from the easiest of tasks. From completing quests to destroying aliens, credits are also used in Auction to earn Elite items while not having to purchase Uridium.
The more rare currency, Uridium, is primarily earned by being purchased as a form of payment , you can also receive it from killing aliens and completing Galaxy Gates, and it has the value to earn players Elite equipment and ammunition, that is of better value than the equipment Credits purchase.
While Ore has no value in the Shop or Auction areas, it has a great value when wanting to upgrade, refine, or even sell it. Players mainly collect Ore from the Skylab, which then is transported to their ship and sold at a friendly base for Credits. This is the preferred method when wanting large sums of Credits.