When a lot of trading card games were first being released, there were limited prints because companies werent yet sure whether theyd sell well
(Pre-Order) Pokemon 30th Celebration Elite Trainer Box
To determine the total cost of a spell, start with the mana cost or alternative cost you're paying (such as a flashback cost), add any cost increases (such as kicker costs), then apply any cost reductions (such as that of The Earth Crystal's first ability)
Then you simply pitch all your excess energy cards into the bin to deal as much damage as is needed, followed by trainer cards that can retrieve them all so you can have another go
Since this is the first time this type of effect has been printed in Magic, you can bet that these cards are going to be going for a bit more than even their regular foil counterparts
Apply to bulk cards as described above