Cheapest priced copy (War of the Spark): $0.35 at Card Kingdom, near mint, their price list as of .
Prison Realm 
Enchantment · Uncommon · War of the Spark · #26
When this enchantment enters, exile target creature or planeswalker an opponent controls until this enchantment leaves the battlefield.
When this enchantment enters, scry 1.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
1 printing · $0.35 to $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| War of the Spark | 26 | Uncommon | $0.35 | $0.49 |
4 rulings from Wizards of the Coast
- 3 May 2019You’ll still scry 1 even if Prison Realm’s first ability has no legal target or if that target becomes an illegal target before the ability resolves.
- 3 May 2019If a token is exiled this way, it will cease to exist and won’t return to the battlefield.
- 3 May 2019If Prison Realm leaves the battlefield before its first triggered ability resolves, the target permanent won’t be exiled.
- 3 May 2019Auras attached to the exiled permanent 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.