Cheapest priced copy (Oath of the Gatewatch): $0.35 at Card Kingdom, near mint, their price list as of .
Cultivator Drone 
Creature — Eldrazi Drone · 2/3 · Common · Oath of the Gatewatch · #42
Devoid (This card has no color.)
{T}: Add {C}. Spend this mana only to cast a colorless spell, activate an ability of a colorless permanent, or pay a cost that contains {C}. ({C} represents colorless mana.)
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Oath of the Gatewatch | 42 | Common | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 22 January 2016Some triggered abilities include a cost as part of their resolution. For example, Bearer of Silence’s ability says, in part, “When you cast Bearer of Silence, you may pay {1}{C}.” You may use mana produced by Cultivator Drone to help pay that cost. In fact, you could tap two Cultivator Drones to pay the entire cost.
- 22 January 2016Mana produced by Cultivator Drone may be used to cast any colorless spell, including most artifact spells, face-down spells, and spells with devoid.