Backup Squad is a Continuous 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, Backup Squad is Unlimited.
YGOPRODeck lists Backup Squad for these formats: Duel Links, Speed Duel, Common Charity, TCG, OCG, Master Duel.
A listed print of Backup Squad appears in 2018 Mega-Tin Mega Pack (MP18-EN145) at Rare rarity.
Among markets shown on this page, the lowest listed snapshot for Backup Squad is about $0.06 on Cardmarket (prices change frequently).
