Cheapest priced copy (Magic 2013): $0.35 at Card Kingdom, near mint, their price list as of .
War Falcon 
Creature — Bird · 2/1 · Common · Magic 2013 · #38
Flying
This creature can't attack unless you control a Knight or a Soldier.
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
1 printing · $0.35 to $0.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Magic 2013 | 38 | Common | $0.35 | $0.79 |
2 rulings from Wizards of the Coast
- 1 July 2012If an effect makes War Falcon a Knight or a Soldier, it will be able to attack even if it's the only creature you control.
- 1 July 2012To attack with War Falcon, you must control a Knight or a Soldier when you declare attackers. Once War Falcon is attacking, it won't be removed from combat if at any point you no longer control a Knight or Soldier.