Gold

Gold is the sole currency of Gaia Online. Anything you do on Gaia will earn you gold, so it isn't difficult to acquire it. One US dollar has been determined to be roughly the equivalent of 2,000 gold, according to the gift credit system.

Ways to Earn Gold
And several other ways.
 * Posting
 * Creating threads
 * Voting in Polls
 * Selling rare items
 * Selling art
 * Browsing the site
 * Winning in the Avatar/Housing/Art Arena
 * Fishing
 * Sniping