Cheapest priced copy (Duel Decks: Speed vs. Cunning): $0.35 at Card Kingdom, near mint, their price list as of .
Swift Justice 
Instant · Common · Return to Ravnica · #26
Until end of turn, target creature gets +1/+0 and gains first strike and lifelink.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
3 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Duel Decks: Speed vs. Cunning | 62 | Common | $0.35 | — |
| The List | RTR-26 | Common | $0.35 | — |
| Return to Ravnica | 26 | Common | $0.35 | $0.49 |