Thanks a lot for playing. The game is setup such that you have a Gold starter deck, and then can unlock a Forest starter deck after the 4th mission. The crystal faction does require slightly more play time to acquire as a free player., but there are a lot of ways to get what you need. The campaign awards you with specific cards from all 3 factions, including resource producers. You can use the free gems earned from quests to get the units you need from the Starter Bundle in the shop, or less reliably from the booster packs. Finally, you can use the Crafting Menu from within the Deck Editor, in order to exchange any extra units for ones you don't have. I hope that helps!