Spellbinder is a rare Artifact — Equipment card from Darksteel (DST), collector number 143. Current market price: $6.27 (foil $30.55), TCGplayer market prices via Scryfall.
Imprint — When this Equipment enters, you may exile an instant card from your hand. Whenever equipped creature deals combat damage to a player, you may copy the exiled card. If you do, you may cast the copy without paying its mana cost. Equip {4}