Cheapest priced copy (Battle for Zendikar): $0.35 at Card Kingdom, near mint, their price list as of .
Slab Hammer 
Artifact — Equipment · Uncommon · Battle for Zendikar · #227
Whenever equipped creature attacks, you may return a land you control to its owner's hand. If you do, the creature gets +2/+2 until end of turn.
Equip {2}
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Battle for Zendikar | 227 | Uncommon | $0.35 | $0.49 |