Cheapest priced copy (Duel Decks: Phyrexia vs. the Coalition): $0.35 at Card Kingdom, near mint, their price list as of .
Gerrard's Command 
Instant · Common · Planeshift · #109
Untap target creature. It gets +3/+3 until end of turn.
Legal inCommanderLegacyVintagePauper
Not legal inBrawlStandardPioneerModern
2 printings · $0.35 to $2.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Duel Decks: Phyrexia vs. the Coalition | 53 | Common | $0.35 | — |
| Planeshift | 109 | Common | $0.35 | $2.99 |
One ruling from Wizards of the Coast
- 4 October 2004This can target a creature which is already untapped.