Cheapest priced copy (Fifth Dawn): $0.35 at Card Kingdom, near mint, their price list as of .
Stand Firm 
Instant · Common · Duel Decks: Heroes vs. Monsters · #21
Target creature gets +1/+1 until end of turn. Scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Fifth Dawn | 17 | Common | $0.35 | $0.49 |
| Duel Decks: Heroes vs. Monsters | 21 | Common | $0.35 | — |