Cheapest priced copy (Magic Origins): $0.35 at Card Kingdom, near mint, their price list as of .
Throwing Knife 
Artifact — Equipment · Uncommon · Magic Origins · #241
Equipped creature gets +2/+0.
Whenever equipped creature attacks, you may sacrifice this Equipment. If you do, this Equipment deals 2 damage to any target.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Magic Origins | 241 | Uncommon | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 22 June 2015Throwing Knife is the source of the damage dealt because of its triggered ability. For example, you could sacrifice Throwing Knife to deal 2 damage to a creature with protection from red, even if Throwing Knife is equipped to a red creature.
- 22 June 2015Throwing Knife's triggered ability triggers before blockers are declared. If you use the ability and destroy the targeted creature with lethal damage, it won't be on the battlefield to block.