Instant and sorcery spells you cast costless to cast.
3/14/2017 Two Goblin Electromancers will make instant and sorcery spells you cast cost less to cast, and so on.
3/14/2017 Goblin Electromancer can’t reduce colored mana costs or in the cost of instant or sorcery spells.
3/14/2017 If there are additional costs to cast a spell, such as a kicker cost or a cost imposed by another effect (such as the one imposed by Thalia, Guardian of Thraben’s ability), apply those increases before applying cost reductions.
3/14/2017 Goblin Electromancer can reduce alternative costs such as overload costs and flashback costs.