Cursed Bill 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, Cursed Bill is Unlimited.
YGOPRODeck lists Cursed Bill for these formats: Duel Links, Common Charity, TCG, OCG, Master Duel.
A listed print of Cursed Bill appears in Starstrike Blast (STBL-EN059) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Cursed Bill is about $0.09 on Cardmarket (prices change frequently).
