Cheapest priced copy (Ravnica: City of Guilds): $0.35 at Card Kingdom, near mint, their price list as of .
Boros Fury-Shield 
Instant · Common · Ravnica: City of Guilds · #5
Prevent all combat damage that would be dealt by target attacking or blocking creature this turn. If {R} was spent to cast this spell, Boros Fury-Shield deals damage to that creature's controller equal to the creature's power.
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
1 printing · $0.35 to $0.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Ravnica: City of Guilds | 5 | Common | $0.35 | $0.99 |
One ruling from Wizards of the Coast
- 1 October 2005If red mana was spent, Boros Fury-Shield, not the target creature, deals the damage to the creature’s controller.