Royal Prison is a Continuous Trap Card.
Trap Cards are normally Set first and can be activated on a later turn, often in response to an action.
On the current TCG and OCG Forbidden & Limited lists tracked here, Royal Prison is Unlimited.
YGOPRODeck lists Royal Prison for these formats: TCG, OCG, Master Duel.
A listed print of Royal Prison appears in Ghosts From the Past (GFTP-EN120) at Ultra Rare rarity.
Among markets shown on this page, the lowest listed snapshot for Royal Prison is about $0.13 on Cardmarket (prices change frequently).
