Cheapest priced copy (Revised Edition): $0.35 at Card Kingdom, near mint, their price list as of .
Circle of Protection: Blue 
Enchantment · Uncommon · Eighth Edition · #11
{1}: The next time a blue source of your choice would deal damage to you this turn, prevent that damage.
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
20 printings · $0.35 to $22.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Unlimited Edition | 11 | Common | $0.99 | — |
| 30th Anniversary Edition | 11 | Common | $0.99 | — |
| 30th Anniversary Edition | 308 | Common | $19.99 | — |
| Revised Edition | 10 | Common | $0.35 | — |
| Fourth Edition Foreign Black Border | 15 | Common | — | — |
| Fourth Edition | 15 | Common | $0.35 | — |
| Fifth Edition | 18 | Common | $0.35 | — |
| Classic Sixth Edition | 9 | Common | $0.35 | — |
| Seventh Edition | 7 | Common | $0.35 | — |
| Seventh Edition | 7★ | Common | — | $13.99 |
| Eighth Edition | 11 | Uncommon | $0.35 | — |
| Eighth Edition | 11★ | Uncommon | — | $2.99 |
| Collectors' Edition | 11 | Common | $1.29 | — |
| Intl. Collectors' Edition | 11 | Common | $1.29 | — |
| Foreign Black Border | 10 | Common | — | — |
| Ice Age | 13 | Common | $0.35 | — |
| Limited Edition Alpha | 10 | Common | $22.99 | — |
| Limited Edition Beta | 11 | Common | $6.49 | — |
| Summer Magic / Edgar | 10 | Common | — | — |
| Tempest | 9 | Common | $0.35 | — |
2 rulings from Wizards of the Coast
- 4 October 2004Can be used even when there is no damage to prevent. It prevents the next damage (if any) from the source this turn.
- 4 October 2004A source of damage is a permanent, a spell on the stack (including one that creates a permanent), or any object referred to by an object on the stack. A source doesn’t need to be capable of dealing damage to be a legal choice.