Cheapest priced copy (March of the Machine: The Aftermath): $2.49 at Card Kingdom, near mint, their price list as of .
Kiora, Sovereign of the Deep 
Legendary Creature — Merfolk Noble · 4/5 · Mythic · March of the Machine: The Aftermath · #85
Vigilance, ward {3}
Whenever you cast a Kraken, Leviathan, Octopus, or Serpent spell from your hand, look at the top X cards of your library, where X is that spell's mana value. You may cast a spell with mana value less than X from among them without paying its mana cost. Put the rest on the bottom of your library in a random order.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
5 printings · $2.49 to $37.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| March of the Machine: The Aftermath | 35 | Mythic | $2.49 | $2.99 |
| March of the Machine: The Aftermath | 85 | Mythic | $10.99 | $7.99Out of stock |
| March of the Machine: The Aftermath | 135 | Mythic | — | — |
| March of the Machine: The Aftermath | 170 | Mythic | $5.49 | $7.99 |
| March of the Machine: The Aftermath | 214 | Mythic | — | $37.99 |
3 rulings from Wizards of the Coast
- 12 May 2023If you cast a spell "without paying its mana cost," you can't pay any alternative costs. You can, however, pay additional costs. If the spell has any mandatory additional costs, those must be paid to cast it.
- 12 May 2023The spell you cast without paying its mana cost is cast during the resolution of the triggered ability. Timing restrictions of that spell based on card type are ignored. It will resolve before the spell that caused the ability to trigger.
- 12 May 2023If the spell has {X} in its mana cost, you must choose 0 as the value of X when casting it without paying its mana cost.