StormGain is a crypto exchange platform. There are two interesting features available on StornGain, one, referral commission, and two, free Bitcoin miner. You can also earn interest on your assets as well as staking rewards. I have been using StornGain for free mining for more than a year. YOu can withdraw your mining rewards once you reach $10 in value. However, you cannot withdraw this money to your third party wallet, you will have to trade and you can withdraw only trading profits.