You can gain those cards you see displayed for gems in the store within packs and no singles should stay with a gem cost as the developers needs a source of revenue and not everything should be gold priced. (Their is alternatives with packs being gold + gem costing)
How about, buying single cards for gold??
How can i get otherwise enough gems in the game to ‘buy’ the expansive gem cards (without spending real money or do ‘the actions’ on ‘’Earne free’‘)?
Otherwise, it takes so long to get the ’better’ cards i think.
Furtermore i would like to say, Amazing game!!