Memory Loss is a Normal Trap Card.
Trap Cards are normally Set first and can be activated on a later turn, often in response to an action.
On the current TCG and OCG Forbidden & Limited lists tracked here, Memory Loss is Unlimited.
YGOPRODeck lists Memory Loss for these formats: Duel Links, Speed Duel, Common Charity, TCG, OCG, Master Duel.
A listed print of Memory Loss appears in 2014 Mega-Tin Mega Pack (MP14-EN045) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Memory Loss is about $0.04 on Cardmarket (prices change frequently).
