The Scarlet Witch is a rare Legendary Creature — Mutant Warlock Hero card from Marvel Super Heroes (MSH), collector number 151. Current market price: $0.38 (foil $0.91), TCGplayer market prices via Scryfall.
Instant and sorcery spells you cast with mana value 4 or greater cost {X} less to cast, where X is The Scarlet Witch's power.