To get to JustPlay app’s cash out page, all you have to do is click “Cashout” on the homepage and choose how you want to redeem your coins.
Overall, you’ll never really know how much you're earning with JustPlay. Coin values are inconsistent. Sometimes 350k coins are worth $0.90, whereas 900k coins could be worth $0.20.
Just be sure to cash out every 3 hours so you don’t miss out on a good coin value when it happens.