Cheapest priced copy (Eldritch Moon): $0.35 at Card Kingdom, near mint, their price list as of .
Slayer's Cleaver 
Artifact — Equipment · Uncommon · Eldritch Moon · #198
Equipped creature gets +3/+1 and must be blocked by an Eldrazi if able.
Equip {4}
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Eldritch Moon | 198 | Uncommon | $0.35 | $0.49 |
4 rulings from Wizards of the Coast
- 13 July 2016If each Eldrazi that could block the equipped creature is tapped or is affected by a spell or ability that says it can’t block, then none of them block. If there’s a cost associated with having each of those creatures block, its controller isn’t forced to pay the cost, so they don’t have to block in that case either.
- 13 July 2016The defending player, not the attacking player, chooses which Eldrazi blocks the equipped creature.
- 13 July 2016One creature equipped with multiple Slayer’s Cleavers only requires a single Eldrazi to block it.
- 13 July 2016Only one Eldrazi is required to block the equipped creature. Other Eldrazi and non-Eldrazi creatures may also block that creature, and are free to block other creatures or not block at all.