Pestilence 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, Pestilence is Unlimited.
YGOPRODeck lists Pestilence for these formats: Common Charity, TCG, OCG, Master Duel.
A listed print of Pestilence appears in Duelist Revolution (DREV-EN058) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Pestilence is about $0.17 on TCGPlayer (prices change frequently).
