Cheapest priced copy (New Capenna Commander): $0.49 at Card Kingdom, near mint, their price list as of .
Flawless Forgery 
Sorcery · Rare · New Capenna Commander · #127
Casualty 3 (As you cast this spell, you may sacrifice a creature with power 3 or greater. When you do, copy this spell and you may choose a new target for the copy.)
Exile target instant or sorcery card from an opponent's graveyard. Copy that card. You may cast the copy without paying its mana cost.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
3 printings · $0.49 to $0.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| New Capenna Commander | 26 | Rare | $0.49 | — |
| New Capenna Commander | 127 | Rare | $0.59 | — |
| New Capenna Commander Promos | 26p | Rare | — | $0.99 |
5 rulings from Wizards of the Coast
- 29 April 2022After Flawless Forgery resolves, the exiled card remains exiled.
- 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 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 2022You may sacrifice only one creature to pay a spell's casualty cost, and you copy the spell only once.