Cheapest priced copy (Hour of Devastation): $1.49 at Card Kingdom, near mint, their price list as of .
Uncage the Menagerie 
Sorcery · Mythic · Hour of Devastation · #137
Search your library for up to X creature cards with different names that each have mana value X, reveal them, put them into your hand, then shuffle.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
2 printings · $1.49 to $5.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Hour of Devastation | 137 | Mythic | $1.49 | $2.99 |
| Hour of Devastation Promos | 137s | Mythic | — | $5.99 |
2 rulings from Wizards of the Coast
- 14 July 2017If you cast Uncage the Menagerie with X as 0, you’ll search your library and shuffle it, but you won’t be able to find any cards.
- 14 July 2017For cards in your library with {X} in their mana costs, X is considered to be 0.