Cheapest priced copy (The List): $0.35 at Card Kingdom, near mint, their price list as of .
Merciless Resolve 
Instant · Common · Shadows over Innistrad · #123
As an additional cost to cast this spell, sacrifice a creature or land.
Draw two cards.
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| The List | SOI-123 | Common | $0.35 | — |
| Shadows over Innistrad | 123 | Common | $0.35 | $0.49 |
2 rulings from Wizards of the Coast
- 8 April 2016You must sacrifice exactly one creature or land to cast Merciless Resolve. You can’t cast it without sacrificing a permanent, and you can’t sacrifice additional permanents.
- 8 April 2016Players can respond to this spell only after it’s been cast and all its costs have been paid. No one can try to destroy the creature or land you sacrificed to stop you from casting this spell or to make you sacrifice a different one.