In Nitro Nation Online, you have two currency types at your disposal.
Gold coins (gold) or tokens are the game’s premium currency, and you can earn them by selling your unneeded parts on the game market, by connecting your game to Facebook, by following it on Twitter and the NNO YouTube channel. Tapjoy tasks will also help you to make extra gold in the game.
Credits (cash or silver) are usually earned by winning races, and they can be won in daily free crates as well as in elite crates.
Both currencies can also be bought with real money.