Gold

Gold is the premium currency in the game.

You can earn it:
 * Buy it with real-word money
 * Reaching certain renown levels
 * Randomly getting it while fighting in WarZone
 * Daily rewards
 * Spinning the wheel

Gold can be spent on a variety of items. With gold, you can buy
 * investors
 * time warps
 * extra invasion fights
 * gaining contractors without deploying (bribe)