You can earn by playing by weekends when the weekend ranked event is on. Rewards depends on you first 25 games, more wins you get, better the reward will be. I earned few dollars so far but for the high gas fees it is hard to make withdrawal soon from few sells. If you like games like the Heartstone and you got some serious experience you can get some pretty expensive cards from event. After that you can sell it on the market where you can give it fair price and it will be disappeared in any minute. In more higher ranks it feels more like pay to win experience but you always can spend earned ETH on cards and make better deck. For non-minted cards there will be forge, which is actually down cause of high gas fees on ETH but they planning to bring it on when gas fees wil be solved. It mens that if you have two same cards you can forge it in to the better one for flux which you earn by playing different gods in game, sounds great right?

Conclusion

This  game has huge potentional and growing community day by the day, you can earn minted cards on weekend event (depends on skill) which you can sell for eth. In my opinion it is absolutely worth of try if you have some spare time, mostly on weekends.