FOILCheapest priced copy (Outlaws of Thunder Junction): $3.99 at Card Kingdom, near mint, their price list as of .
Aven Interrupter 
Creature — Bird Rogue · 2/2 · Rare · Outlaws of Thunder Junction Promos · #4s
Flash
Flying
When this creature enters, exile target spell. It becomes plotted. (Its owner may cast it as a sorcery on a later turn without paying its mana cost.)
Spells your opponents cast from graveyards or from exile cost {2} more to cast.
Legal inCommanderBrawlStandardPioneerModernLegacyVintage
Not legal inPauper
5 printings · $3.99 to $13.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Outlaws of Thunder Junction | 4 | Rare | $3.99 | $5.99 |
| Outlaws of Thunder Junction | 309 | Rare | $6.49 | $13.99 |
| Outlaws of Thunder Junction Promos | 4p | Rare | $4.49 | $6.99 |
| Outlaws of Thunder Junction Promos | 4s | Rare | — | $6.49 |
| Planeswalker Championship Promos | 2024-08 | Rare | — | — |
8 rulings from Wizards of the Coast
- 12 April 2024You can't cast a plotted card on the same turn it became plotted. On any future turn, you may cast that card from exile without paying its mana cost during your main phase while the stack is empty.
- 12 April 2024Spells that can't be countered can still be exiled by Aven Interrupter's triggered ability. They won't resolve.
- 12 April 2024Plot abilities are written "Plot [cost]," which means "Any time you have priority during your main phase while the stack is empty, you may pay [cost] and exile this card from your hand. It becomes plotted."
- 12 April 2024Exiling a card using its plot ability is a special action. Once you announce you're taking that action, no other player can respond by trying to remove that card from your hand.
- 12 April 2024If you're casting a plotted card from exile without paying its mana cost, you can't choose to cast it for any other alternative costs. You can, however, pay additional costs, such as kicker costs. If the plotted card has any mandatory additional costs, those must still be paid to cast the spell.
- 12 April 2024If a plotted card has {X} in its mana cost, you must choose 0 as the value of X when casting it without paying its mana cost.
- 12 April 2024If the plotted card's owner casts it, the spell has no relation to the spell that player originally cast. Any choices made for the original spell or effects affecting the original spell aren't carried over to the new one.
- 7 June 2024If an instant or a card with flash is plotted this way, you can still cast it only when you have priority during your main phase while the stack is empty.