Fighting Spirit is a Equip Spell Card.
Spell Cards are usually activated from the hand on your turn unless their type gives another timing window.
On the current TCG and OCG Forbidden & Limited lists tracked here, Fighting Spirit is Unlimited.
YGOPRODeck lists Fighting Spirit for these formats: Speed Duel, Duel Links, Common Charity, Edison, TCG, OCG, Master Duel.
A listed print of Fighting Spirit appears in 2-Player Starter Set (STAX-EN033) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Fighting Spirit is about $0.02 on Cardmarket (prices change frequently).
