Arcane Melee

• WWizards of the Coast2012-05-01
  Official Ruling
  The cost to cast an instant or sorcery spell with one generic mana in its mana cost will be reduced by . For example, an instant spell with a mana cost of would cost to cast.
• WWizards of the Coast2012-05-01
  Official Ruling
  Arcane Melee can reduce alternative costs such as miracle costs.
• WWizards of the Coast2012-05-01
  Official Ruling
  If there are additional costs to cast a spell, such as a kicker cost or a cost imposed by another effect (such as Thalia, Guardian of Thraben’s ability), apply those increases before applying cost reductions.
• WWizards of the Coast2012-05-01
  Official Ruling
  Arcane Melee can’t reduce the colored mana requirement of an instant or sorcery spell.

Rulings via Scryfall