Pendulum Back is a Normal 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, Pendulum Back is Unlimited.
YGOPRODeck lists Pendulum Back for these formats: Duel Links, Common Charity, TCG, OCG, Master Duel.
A listed print of Pendulum Back appears in Duelist Alliance (DUEA-EN078) at Super Rare rarity.
Among markets shown on this page, the lowest listed snapshot for Pendulum Back is about $0.20 on TCGPlayer (prices change frequently).
