Cheapest priced copy (Avatar: The Last Airbender Eternal): $0.49 at Card Kingdom, near mint, their price list as of .
Bison Whistle 
Artifact · Rare · Avatar: The Last Airbender Eternal · #202
{1}, {T}: Look at the top card of your library. If it's a Bison card, you may put it onto the battlefield. If it's a creature card, you may reveal it and put it into your hand. Otherwise, you may put it into your graveyard.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
2 printings · $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Avatar: The Last Airbender Eternal | 131 | Rare | $0.49 | $0.49 |
| Avatar: The Last Airbender Eternal | 202 | Rare | $0.49 | $0.49 |