Cheapest priced copy (Fourth Edition): $0.35 at Card Kingdom, near mint, their price list as of .
Brainwash 
Enchantment — Aura · Common · Fifth Edition · #13
Enchant creature
Enchanted creature can't attack unless its controller pays {3}.
Legal inCommanderLegacyVintagePauper
Not legal inBrawlStandardPioneerModern
5 printings · $0.35 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Fourth Edition Foreign Black Border | 11 | Common | — | — |
| Fourth Edition | 11 | Common | $0.35 | — |
| Fifth Edition | 13 | Common | $0.35 | — |
| The Dark | 3 | Common | $0.35 | — |
| Renaissance | 6 | Common | — | — |
3 rulings from Wizards of the Coast
- 4 October 2004Paying this cost is not an instant or any other kind of ability, it is an additional cost on the declaration of the attacker.
- 4 October 2004This ability is paid for during the declare attackers step of the combat phase.
- 4 October 2004If there are multiple combat phases during the turn, the attack cost must be paid each time if you want to attack with the creature.