Cheapest priced copy (Fate Reforged): $0.35 at Card Kingdom, near mint, their price list as of .
Collateral Damage 
Instant · Common · Fate Reforged · #95
As an additional cost to cast this spell, sacrifice a creature.
Collateral Damage deals 3 damage to any target.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Fate Reforged | 95 | Common | $0.35 | $0.49 |
| Jumpstart | 305 | Common | $0.35 | — |
3 rulings from Wizards of the Coast
- 24 November 2014Players can respond to Collateral Damage only after it’s been cast and all its costs have been paid. No one can try to destroy the creature you sacrificed to stop you from casting this spell.
- 24 November 2014If you sacrifice an attacking or blocking creature during the declare blockers step, it won’t deal combat damage. If you wait until the combat damage step, but that creature is dealt lethal damage, it’ll be destroyed before you get a chance to sacrifice it.
- 24 November 2014You must sacrifice exactly one creature to cast this spell; you can’t cast it without sacrificing a creature, and you can’t sacrifice additional creatures.