Cheapest priced copy (Legions): $0.59 at Card Kingdom, near mint, their price list as of .
Hollow Specter 
Creature — Specter · 2/2 · Rare · Legions · #75
Flying
Whenever this creature deals combat damage to a player, you may pay {X}. If you do, that player reveals X cards from their hand and you choose one of them. That player discards that card.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
1 printing · $0.59 to $5.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Legions | 75 | Rare | $0.59 | $5.99 |
2 rulings from Wizards of the Coast
- 4 October 2004You decide on the value of X and pay {X} during resolution.
- 4 October 2004X can be zero, but then that player discards nothing.