Cheapest priced copy (Lorwyn): $0.35 at Card Kingdom, near mint, their price list as of .
Thieving Sprite 
Creature — Faerie Rogue · 1/1 · Common · Lorwyn · #143
Flying
When this creature enters, target player reveals X cards from their hand, where X is the number of Faeries you control. You choose one of those cards. That player discards that card.
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
2 printings · $0.35 to $0.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Lorwyn | 143 | Common | $0.35 | $0.99 |
| Modern Masters | 101 | Common | $0.35 | $0.49 |
One ruling from Wizards of the Coast
- 7 June 2013The number of cards that are revealed is equal to the number of Faeries you control when the ability resolves.