Cheapest priced copy (Magic 2012): $0.35 at Card Kingdom, near mint, their price list as of .
Master Thief 
Creature — Human Rogue · 2/2 · Uncommon · Magic 2012 · #64
When this creature enters, gain control of target artifact for as long as you control this creature.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Magic 2012 | 64 | Uncommon | $0.35 | $0.49 |
| Zendikar Rising Commander | 30 | Uncommon | $0.35 | — |
3 rulings from Wizards of the Coast
- 22 September 2011If Master Thief ceases to be under your control before its ability resolves, you won’t gain control of the targeted artifact at all.
- 22 September 2011If Master Thief leaves the battlefield, you no longer control it, and its control-change effect ends.
- 22 September 2011If another player gains control of Master Thief, its control-change effect ends. Regaining control of Master Thief won’t cause you to regain control of the artifact.