Cheapest priced copy (Modern Horizons): $0.35 at Card Kingdom, near mint, their price list as of .
Treetop Ambusher 
Creature — Elf Berserker · 2/1 · Common · Modern Horizons · #186
Dash {1}{G} (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)
Whenever this creature attacks, target creature you control gets +1/+1 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 | 186 | Common | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 14 June 2019Treetop Ambusher can be the target of its own ability.
- 14 June 2019If you pay the dash cost to cast a creature spell, that card will be returned to its owner’s hand only if it’s still on the battlefield when its triggered ability resolves. If it dies or goes to another zone before then, it will stay where it is.