Eternal Rest is a Normal 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, Eternal Rest is Unlimited.
YGOPRODeck lists Eternal Rest for these formats: GOAT, OCG GOAT, Speed Duel, Duel Links, Common Charity, Edison, TCG, OCG, Master Duel.
A listed print of Eternal Rest appears in Dark Beginning 1 (DB1-EN036) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Eternal Rest is about $0.05 on Cardmarket (prices change frequently).
