Cheapest priced copy (Guildpact): $0.49 at Card Kingdom, near mint, their price list as of .
Killer Instinct 
Enchantment · Rare · Guildpact · #120
At the beginning of your upkeep, reveal the top card of your library. If it's a creature card, put it onto the battlefield. That creature gains haste until end of turn. Sacrifice it at the beginning of the next end step.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
1 printing · $0.49 to $0.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Guildpact | 120 | Rare | $0.49 | $0.79 |
One ruling from Wizards of the Coast
- 1 February 2006If the top card of your library isn't a creature card, it remains on top of your library. You won't have to sacrifice it at end of turn.