Cheapest priced copy (Innistrad: Double Feature): $0.35 at Card Kingdom, near mint, their price list as of .
Circle of Confinement 
Enchantment · Uncommon · Innistrad: Crimson Vow · #7
When this enchantment enters, exile target creature an opponent controls with mana value 3 or less until this enchantment leaves the battlefield.
Whenever an opponent casts a Vampire spell with the same name as a card exiled with this enchantment, you gain 2 life.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
3 printings · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Innistrad: Double Feature | 274 | Uncommon | $0.35 | $0.49 |
| Innistrad: Crimson Vow | 7 | Uncommon | $0.35 | $0.49 |
| Innistrad: Crimson Vow (Van Helsing's Holy Ward) | 329 | Uncommon | $0.35 | $0.49 |
3 rulings from Wizards of the Coast
- 19 November 2021If Circle of Confinement leaves the battlefield before its enters-the-battlefield ability resolves, the target creature won't be exiled.
- 19 November 2021Auras attached to the exiled creature will be put into their owners' graveyards. Any Equipment will become unattached and remain on the battlefield. Any counters on the exiled permanent will cease to exist. When the card returns to the battlefield, it will be a new object with no connection to the card that was exiled.
- 19 November 2021If a token is exiled this way, it will cease to exist and won't return to the battlefield.