Cheapest priced copy (Adventures in the Forgotten Realms): $0.35 at Card Kingdom, near mint, their price list as of .
Sudden Insight 
Instant · Uncommon · Adventures in the Forgotten Realms · #77
Draw a card for each different mana value among nonland cards in your graveyard.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
2 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Adventures in the Forgotten Realms | 77 | Uncommon | $0.35 | $0.49 |
| Foundations Jumpstart | 110 | Uncommon | $0.35 | — |
2 rulings from Wizards of the Coast
- 23 July 2021If a card in your graveyard has {X} in its mana cost, X is 0 when determining that card's mana value.
- 23 July 2021Although land cards aren't considered, nonland cards with mana value 0 are. For example if the cards in your graveyard are an artifact card with mana cost {X} and a sorcery card with mana cost {2}{U}, you'll draw two cards.