Battle Waltz 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, Battle Waltz is Unlimited.
YGOPRODeck lists Battle Waltz for these formats: Duel Links, Common Charity, TCG, OCG, Master Duel.
A listed print of Battle Waltz appears in Duelist Pack: Yusei 3 (DP10-EN023) at Rare rarity.
Among markets shown on this page, the lowest listed snapshot for Battle Waltz is about $0.09 on Cardmarket (prices change frequently).
