Cheapest priced copy (Lorwyn): $0.35 at Card Kingdom, near mint, their price list as of .
Warren Pilferers 
Creature — Goblin Rogue · 3/3 · Common · Lorwyn · #146
When this creature enters, return target creature card from your graveyard to your hand. If that card is a Goblin card, this creature gains haste until end of turn.
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
2 printings · $0.35 to $0.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Lorwyn | 146 | Common | $0.35 | $0.79 |
| Modern Masters | 103 | Common | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 1 October 2007The ability checks whether the targeted card is a Goblin when the ability resolves.
- 1 October 2007If the card is an illegla target as the ability resolves, the ability won’t resolve and none of its effects will happen. Warren Pilferers won’t gain haste.