Cheapest priced copy (Ixalan): $0.49 at Card Kingdom, near mint, their price list as of .
Dreamcaller Siren 
Creature — Siren Pirate · 3/3 · Rare · Ixalan · #54
Flash
Flying
This creature can block only creatures with flying.
When this creature enters, if you control another Pirate, tap up to two target nonland permanents.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
2 printings · $0.49 to $1.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Ixalan Promos | 54s | Rare | — | $1.49 |
| Ixalan | 54 | Rare | $0.49 | $0.49 |
One ruling from Wizards of the Coast
- 29 September 2017Dreamcaller Siren's last ability won't trigger if you don't control another Pirate as it enters the battlefield. If you lose control of each other Pirate before that ability resolves, it won't do anything.