Limitation at buying Troops???

[Kolorabi]

And sometimes you can get access to more by doing quests. I was running out of griffins to buy, but completed a quest for the griffin king, and got access to over 1400 griffins plus a bunch of griffin eggs.

So yeah, you've got to conserve your favourite troops if you can, but you will never ever run out of troops to buy. Even if you do run out of one type of troops, you can always try something else. And there's also an unlimited supply of certain weaker troop types (that can still pack quite a punch if they're many).

I think this feature adds to the strategic gameplay, and it motivates you to use healing spells and other strategies to keep your troops alive.