Cheapest priced copy (Adventures in the Forgotten Realms): $0.35 at Card Kingdom, near mint, their price list as of .
Power Word Kill 
Instant · Rare · Game Day Promos · #1
Destroy target non-Angel, non-Demon, non-Devil, non-Dragon creature.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
4 printings · $0.35 to $0.69 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Adventures in the Forgotten Realms | 114 | Uncommon | $0.35 | $0.49 |
| Adventures in the Forgotten Realms | 400 | Uncommon | $0.49 | $0.49 |
| Game Day Promos | 1 | Rare | $0.69 | $0.69 |
| The List | AFR-114 | Uncommon | $0.35 | — |
One ruling from Wizards of the Coast
- 23 July 2021A creature is a legal target for Power Word Kill if it doesn't have any of these four creature types. If it has one of these four creature types, it's not a legal target, even if it also has a creature type that's not among these four. For example, a Demon Rogue is not a valid target for this spell.