Extra Net 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, Extra Net is Unlimited.
YGOPRODeck lists Extra Net for these formats: Duel Links, TCG, OCG, Master Duel.
A listed print of Extra Net appears in Secrets of Eternity (SECE-EN066) at Short Print rarity.
Among markets shown on this page, the lowest listed snapshot for Extra Net is about $0.43 on TCGPlayer (prices change frequently).
