Cheapest priced copy (Modern Horizons 2): $0.35 at Card Kingdom, near mint, their price list as of .
Sinister Starfish 
Creature — Starfish · 0/3 · Common · Murders at Karlov Manor Commander · #140
{T}: Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Legal inCommanderModernLegacyVintagePauper
Not legal inBrawlStandardPioneer
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Modern Horizons 2 | 99 | Common | $0.35 | $0.49 |
| Murders at Karlov Manor Commander | 140 | Common | $0.35 | — |