Cheapest priced copy (Avatar: The Last Airbender Eternal): $0.35 at Card Kingdom, near mint, their price list as of .
That's Rough Buddy 
Instant — Lesson · Uncommon · Avatar: The Last Airbender Eternal · #87
Put a +1/+1 counter on target creature. Put two +1/+1 counters on that creature instead if a creature left the battlefield under your control this turn.
Draw a card.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
1 printing · $0.35 to $0.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Avatar: The Last Airbender Eternal | 87 | Uncommon | $0.35 | $0.79 |