You get free tokens for signing up. You can use these tokens to buy cards when the game launches so you can play for free. They have a referral system too where you can earn for referring people to the airdrop. The links on this post are my affiliate links.
To qualify, you need to confirm your e-mail address , join their telegram group and have a Metamask account. If you don't have a Metamask account you can get one for free.
If you like Blockchain gaming, why not check it out