FOILCheapest priced copy (Innistrad: Double Feature): $0.49 at Card Kingdom, near mint, their price list as of .
Inspired Idea 
Sorcery · Rare · Innistrad: Crimson Vow Promos · #64s
Cleave {3}{U}{U} (You may cast this spell for its cleave cost. If you do, remove the words in square brackets.)
Draw three cards. [Your maximum hand size is reduced by three for the rest of the game.]
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
4 printings · $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Innistrad: Double Feature | 331 | Rare | $0.49 | $0.49 |
| Innistrad: Crimson Vow Promos | 64s | Rare | — | $0.49 |
| Innistrad: Crimson Vow | 64 | Rare | $0.49 | $0.49 |
| Innistrad: Crimson Vow | 360 | Rare | $0.49 | $0.49 |
7 rulings from Wizards of the Coast
- 19 November 2021If an effect allows you to “cast a spell without paying its mana cost,” you can't cast that spell for its cleave cost.
- 19 November 2021If you cast a spell for its cleave cost, that spell doesn't have any of the text in square brackets while it's on the stack.
- 19 November 2021If multiple effects modify your hand size, apply them in timestamp order. For example, if you are affected by Null Profusion (an enchantment that sets a player's maximum hand size to two) and then resolve Inspired Idea without paying its cleave cost, your maximum hand size would be zero. However, if Null Profusion entered the battlefield after Inspired Idea resolved, your maximum hand size would be two.
- 19 November 2021You can't cast a spell for both its cleave cost and another alternative cost. For example, if an effect gives an Alchemist's Retrieval in your graveyard a flashback cost of {U}, you can't cast it from your graveyard for its cleave cost.
- 19 November 2021If a player has more cards in their hand than their maximum hand size during the cleanup step of that player's turn, that player discards until they have that many cards. A player's maximum hand size isn't checked at any time other than their own cleanup step.
- 19 November 2021If you currently have no maximum hand size, then reducing your maximum hand size by three will have no effect. If the effect causing you to have no maximum hand size ends, Inspired Idea's effect will apply at that time.
- 19 November 2021A cleave cost is an alternative cost that's paid instead of the spell's mana cost. Casting a spell for its cleave cost doesn't change the spell's mana value.