Mausoleum of the Emperor is a Field 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, Mausoleum of the Emperor is Unlimited.
YGOPRODeck lists Mausoleum of the Emperor for these formats: Duel Links, Common Charity, Edison, TCG, OCG, Master Duel.
A listed print of Mausoleum of the Emperor appears in Battle Pack 2: War of the Giants (BP02-EN149) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Mausoleum of the Emperor is about $0.05 on Cardmarket (prices change frequently).
