Mistake 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, Mistake is Unlimited.
YGOPRODeck lists Mistake for these formats: Common Charity, TCG, OCG, Master Duel.
A listed print of Mistake appears in 2014 Mega-Tin Mega Pack (MP14-EN177) at Secret Rare rarity.
Among markets shown on this page, the lowest listed snapshot for Mistake is about $0.09 on Cardmarket (prices change frequently).
