Cheapest priced copy (Foundations): $7.49 at Card Kingdom, near mint, their price list as of .
Omniscience 
Enchantment · Mythic · Foundations · #161
You may cast spells from your hand without paying their mana costs.
Legal inCommanderBrawlStandardPioneerModernLegacyVintage
Not legal inPauper
12 printings · $6.99 to $549.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Foundations | 161 | Mythic | $7.49 | $6.99 |
| Foundations | 312 | Mythic | $10.99 | $17.99 |
| Foundations | 379 | Mythic | — | $94.99 |
| Magic 2013 | 63 | Mythic | $9.99 | $39.99 |
| Core Set 2019 | 65 | Mythic | $8.49 | $11.99 |
| Amonkhet Invocations | 34 | Special | — | $179.99 |
| Judge Gift Cards 2022 | 2 | Rare | — | $24.99 |
| Foundations Promos | 161s | Mythic | — | $13.99 |
| Core Set 2019 Promos | 65s | Mythic | — | $16.99 |
| Wilds of Eldraine: Enchanting Tales | 24 | Mythic | $11.99 | $27.99 |
| Wilds of Eldraine: Enchanting Tales | 70 | Mythic | $39.99 | $84.99Out of stock |
| Wilds of Eldraine: Enchanting Tales | 90 | Mythic | — | $549.99 |
4 rulings from Wizards of the Coast
- 13 July 2018If a spell has {X} in its mana cost, you must choose 0 as the value of X when casting it without paying its mana cost.
- 13 July 2018You must follow the normal timing permissions and restrictions of each spell you cast.
- 13 July 2018If you cast a spell "without paying its mana cost," you can't choose to cast it for any alternative costs. You can, however, pay additional costs, such as kicker costs. If the card has any mandatory additional costs, such as that of Tormenting Voice, those must be paid to cast the spell.
- 13 July 2018Once you cast Omniscience, if it's your turn, you'll have priority immediately after it resolves. You can cast another spell before any player can attempt to remove Omniscience with spells or abilities.