Cheapest priced copy (Modern Horizons): $39.99 at Card Kingdom, near mint, their price list as of .
Ranger-Captain of Eos 
Creature — Human Soldier Ranger · 3/3 · Mythic · The List · #MH1-21
When this creature enters, you may search your library for a creature card with mana value 1 or less, reveal it, put it into your hand, then shuffle.
Sacrifice this creature: Your opponents can't cast noncreature spells this turn.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
4 printings · $39.99 to $499.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Final Fantasy: Through the Ages (Knights of San d'Oria) | 2 | Mythic | $44.99 | $499.99 |
| Modern Horizons 1 Timeshifts | 5 | Mythic | — | $99.99 |
| Modern Horizons | 21 | Mythic | $39.99 | $109.99 |
| The List | MH1-21 | Mythic | $39.99 | — |
2 rulings from Wizards of the Coast
- 14 June 2019Your opponents may cast spells in response to the last ability of Ranger-Captain of Eos. The ability won’t affect those spells and it won’t affect spells that those players cast before you activated it. (In other words, the ability can’t be used to counter a spell.)
- 14 June 2019If a card in a player’s library has {X} in its mana cost, X is considered to be 0.