Cheapest priced copy (Modern Horizons 2): $0.59 at Card Kingdom, near mint, their price list as of .
Blacksmith's Skill 
Instant · Common · Modern Horizons 2 · #6
Target permanent gains hexproof and indestructible until end of turn. If it's an artifact creature, it gets +2/+2 until end of turn.
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
2 printings · $0.59 to $0.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Modern Horizons 2 | 6 | Common | $0.79 | $0.79 |
| Modern Horizons 2 | 381 | Common | $0.59 | $0.99 |
One ruling from Wizards of the Coast
- 18 June 2021Blacksmith's Skill checks whether the permanent is an artifact creature when it resolves. If the target isn't an artifact creature when the spell is cast but becomes one before the spell resolves, it will get +2/+2.