Back-Up Rider is a Normal 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, Back-Up Rider is Unlimited.
YGOPRODeck lists Back-Up Rider for these formats: Duel Links, Common Charity, TCG, OCG, Master Duel.
A listed print of Back-Up Rider appears in 2-Player Starter Set (STAS-EN010) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Back-Up Rider is about $0.07 on Cardmarket (prices change frequently).
