Leighbet, Izzet Mastermind

When Leighbet, Izzet Mastermind enters the batttlefield, target instant or sorcery in your graveyard gains Jump-start (You may cast this card from your graveyard by discarding a card in addition to paying its other costs. Then exile this card.)
Whenever a player casts an instant or sorcery spell, you draw a card.
{u}{r}: Instant spells you cast cost {1} less to cast