It resolves even if that spell is countered or otherwise leaves the stack
Most valuable Magic: The Gathering Avatar cards If you're all about collecting chase cards when it comes to Magic: The Gathering | Avatar: The Last Airbender, TCGplayer has you covered with single card listings and prices
Plus, its a creature thats fetchable off a Stoneforge Mystic or the new Cloud, Midgar Mercenary
If you want a hard number, something thats worth at least the planeswalkers mana cost plus a number of mana equal to the number of plusses necessary to reach the ult from the starting loyalty, often more than that
There are 100 each of the serialized borderless poster cards (0.1%) numbered XXX/100
Also in the FINAL FANTASY series: FINAL FANTASY - Commander Deck (Counter Blitz FINAL FANTASY X), FINAL FANTASY - Commander Deck (Limit Break FINAL FANTASY VII), FINAL FANTASY - Commander Deck (Revival Trance FINAL FANTASY VI), FINAL FANTASY - Gift Bundle, FINAL FANTASY - Play Booster Display, FINAL FANTASY - Scene Box (Camp Comrades), FINAL FANTASY - Scene Box (Children of Fate), FINAL FANTASY - Scene Box (Garland at the Chaos Shrine), FINAL FANTASY - Scene Box (The Siege of Alexandria), and FINAL FANTASY - Starter Kit