Weed Out 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, Weed Out is Unlimited.
YGOPRODeck lists Weed Out for these formats: Duel Links, Common Charity, Edison, TCG, OCG, Master Duel.
A listed print of Weed Out appears in Dark Revelation Volume 4 (DR04-EN114) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Weed Out is about $0.04 on Cardmarket (prices change frequently).
