Cheapest priced copy (Modern Horizons 2): $0.35 at Card Kingdom, near mint, their price list as of .
Burdened Aerialist 
Creature — Human Pirate · 3/1 · Common · Modern Horizons 2 · #38
When this creature enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")
Whenever you sacrifice a token, this creature gains flying until end of turn.
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Modern Horizons 2 | 38 | Common | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 18 June 2021If a blocked creature gains flying after blockers are declared, it won't cause that creature to become unblocked, even if the blocking creature doesn't have flying or reach.
- 18 June 2021Burdened Aerialist's ability will trigger whenever you sacrifice a token for any reason, not just when you sacrifice Treasure tokens.