Mishra's Workshop

• WWizards of the Coast2004-10-04
  Official Ruling
  You can spend the mana on costs on the spell's text.
• WWizards of the Coast2004-10-04
  Official Ruling
  This mana may not be used to pay costs imposed after the spell is initially cast.
• WWizards of the Coast2004-10-04
  Official Ruling
  The mana can't be used to pay Echo costs.
• WWizards of the Coast2004-10-04
  Official Ruling
  This mana may be used on additional costs to cast the spell, such as Kicker.

Rulings via Scryfall