You're guaranteed one of these Super Rare variant cards in your Special Edition box, either Skull Meister or Solemn Strike, plus 1 of 2 Super Rare preview cards from the Fall 2017 booster set, AND the 27 cards you pull from your 3 booster packs
Card Name Mana Cost Type Enchantment Rarity Rare rules Text Whenever a player casts a spell from their hand, that player exiles it, then exiles cards from the top of their library until they exile a card that shares a card type with it
You cannot Special Summon monsters while this card Special Summoned by this effect is in the Monster Zone, except Reptile monsters
A lot of balance and care goes into choosing the cost of a card, more than I can express here, but looking for similar effects on existing Magic cards can give you an idea of a fair costfor example, a ramp spell that puts two lands into play ought to cost 4 mana, per Explosive Vegetation