Straight Flush 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, Straight Flush is Unlimited.
YGOPRODeck lists Straight Flush for these formats: Duel Links, Speed Duel, Common Charity, Edison, TCG, OCG, Master Duel.
A listed print of Straight Flush appears in Cyberdark Impact (CDIP-EN050) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Straight Flush is about $0.10 on Cardmarket (prices change frequently).
