Snow-Covered Island

In a Limited event (usually Booster Draft or Sealed Deck), you can't add basic snow lands to your card pool as you would other basic lands. You can play with basic snow lands only if you open them in your sealed deck or draft them.

The Kaldheim set doesn't have any cards with mana costs that include {S}, but some previous sets do. If an effect says such a spell costs {1} less to cast, that reduction doesn't apply to any {S} costs. This is also true for activated abilities that include {S} in their activation costs and effects that reduce those costs.