FOILCheapest priced copy (New Capenna Commander): $0.49 at Card Kingdom, near mint, their price list as of .
Audacious Swap 
Instant · Rare · New Capenna Commander Promos · #44p
Casualty 2 (As you cast this spell, you may sacrifice a creature with power 2 or greater. When you do, copy this spell and you may choose a new target for the copy.)
The owner of target nonenchantment permanent shuffles it into their library, then exiles the top card of their library. If it's a land card, they put it onto the battlefield. Otherwise, they may cast it without paying its mana cost.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
3 printings · $0.49 to $8.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| New Capenna Commander | 44 | Rare | $0.49 | — |
| New Capenna Commander | 145 | Rare | $0.59 | — |
| New Capenna Commander Promos | 44p | Rare | — | $8.99 |
4 rulings from Wizards of the Coast
- 29 April 2022The copy of the spell is created on the stack, so it's not “cast.” Abilities that trigger when a player casts a spell won't trigger.
- 29 April 2022Casualty N means “As an additional cost to cast this spell, you may sacrifice a creature with power N or greater.” and “When you cast this spell, if a casualty cost was paid for it, copy it. If the spell has any targets, you may choose new targets for the copy.”
- 29 April 2022If you pay the casualty cost of a spell, the copy will resolve before the original spell.
- 29 April 2022You may sacrifice only one creature to pay a spell's casualty cost, and you copy the spell only once.