Cheapest priced copy (Modern Horizons 3): $0.35 at Card Kingdom, near mint, their price list as of .
Aerie Auxiliary 
Creature — Bird Soldier · 3/3 · Common · Modern Horizons 3 · #18
Flying
When this creature enters, support 2. (Put a +1/+1 counter on each of up to two other target creatures.)
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Modern Horizons 3 | 18 | Common | $0.35 | $0.49 |