Cheapest priced copy (Avatar: The Last Airbender): $8.49 at Card Kingdom, near mint, their price list as of .
Appa, Steadfast Guardian 
Legendary Creature — Bison Ally · 3/4 · Mythic · Avatar: The Last Airbender · #316
Flash
Flying
When Appa enters, airbend any number of other target nonland permanents you control. (Exile them. While each one is exiled, its owner may cast it for {2} rather than its mana cost.)
Whenever you cast a spell from exile, create a 1/1 white Ally creature token.
Legal inCommanderBrawlStandardPioneerModernLegacyVintage
Not legal inPauper
3 printings · $8.49 to $29.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Avatar: The Last Airbender Promos | 10s | Mythic | — | $29.99 |
| Avatar: The Last Airbender | 10 | Mythic | $8.49 | $8.99 |
| Avatar: The Last Airbender | 316 | Mythic | $16.99 | $24.99 |
5 rulings from Wizards of the Coast
- 2 October 2025Tokens exiled this way will cease to exist and cannot be cast.
- 2 October 2025Since you are using an alternative cost to cast a spell from exile this way, you can't pay any other alternative costs. You can, however, pay additional costs, such as kicker costs. If the card has any mandatory additional costs, you must pay those.
- 2 October 2025To airbend one or more permanents and/or spells means to exile each of those objects. For each card exiled this way, for as long as it's exiled, its owner may cast it from exile by paying {2} rather than paying its mana cost.
- 2 October 2025If the spell you cast has {X} in its mana cost, you must choose 0 as the value of X.
- 2 October 2025Lands exiled this way cannot be played from exile. (Lands that were animated by earthbend will be returned to the battlefield tapped when they're exiled.)