Cheapest priced copy (Core Set 2021): $0.35 at Card Kingdom, near mint, their price list as of .
Mistral Singer 
Creature — Siren · 2/2 · Common · Core Set 2021 · #58
Flying
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Core Set 2021 | 58 | Common | $0.35 | $0.49 |