Cheapest priced copy (Battle for Zendikar): $0.35 at Card Kingdom, near mint, their price list as of .
Hedron Blade 
Artifact — Equipment · Common · Battle for Zendikar · #224
Equipped creature gets +1/+1.
Whenever equipped creature becomes blocked by one or more colorless creatures, it gains deathtouch until end of turn. (Any amount of damage it deals to a creature is enough to destroy it.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Battle for Zendikar | 224 | Common | $0.35 | $0.49 |