Introduction to Gallantry 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, Introduction to Gallantry is Unlimited.
YGOPRODeck lists Introduction to Gallantry for these formats: Common Charity, Edison, TCG, OCG, Master Duel.
A listed print of Introduction to Gallantry appears in Force of the Breaker (FOTB-EN053) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Introduction to Gallantry is about $0.05 on TCGPlayer (prices change frequently).
