There are several different currencies floating around this game. They are:
Credits
The main and only currency used in A3. You can directly earn credits by training against humans in the Battle Village, getting a welfare check at the Welfare Office, playing Hangman and all other kinds of ways. The credit is the main currency of the game and is used to buy everything.
Making Money
The age-old question is, of course, "How do I make lots of money?" There’s no easy answer. In general, the harder the task the more money you’ll make. Talk to guild members on tips or tricks to making money. We have a few here. As you explore the game, you'll discover dozens of ways to make money.