Cheapest priced copy (Modern Horizons): $0.49 at Card Kingdom, near mint, their price list as of .
Munitions Expert 
Creature — Goblin · 1/1 · Uncommon · Modern Horizons 2 Timeshifts · #16
Flash
When this creature enters, you may have it deal damage to target creature or planeswalker equal to the number of Goblins you control.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
2 printings · $0.49 to $2.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Modern Horizons 2 Timeshifts | 16 | Uncommon | $0.69 | $0.79 |
| Modern Horizons | 209 | Uncommon | $0.49 | $2.99 |
One ruling from Wizards of the Coast
- 14 June 2019The number of Goblins you control is counted only as Munitions Expert’s ability resolves. If Munitions Expert is still on the battlefield, it will count itself.