Charizard EX, for example, can hit for 200 damage with Crimson Storm but that attack costs four Energy to use: with a lucky Moltres turn, though, Charizard can instantly have three Energy before it even evolves
They also won't trigger if a card on the battlefield transforms into a legendary permanent
We also have other subscription models that aren't as expensive as the most expensive package that you have chosen, so to say that it's expensive is a little extreme when you have chosen the highest one
The likes of: I don't currently run Champion of Wits, Angel of Sanctions, or Timeless Witness but I am looking into them, and I've recently cut the sadly unpopular Glyph Keeper
The Gitrong Monster generally runs a lot of creatures that can tap for mana, so if you have to sacrafice too many lands you'll still have mana sources