All new players who have invested little or no extra money know the problem when they can’t make any progress with the standard cards. I had the same problem and rented only ONE card and now I win almost every game.
It is the water splinter card “Venari Wavesmith. ” She has high mana costs, but with her save ability, she gives each allied monster plus two shields. Especially in games with high mana costs, this card is very decisive and extremely effective.
For new players like me, it is definitely not worth buying this card, as the cheapest variants currently cost more than $3. But you can rent it for 1-2 DEC per day, because you get a lot more DEC back and so it is probably the most profitable first card.
Thank you for reading and I hope I was able to help you.
See you soon and have a nice day
eragon