Heat Wave 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, Heat Wave is Unlimited.
YGOPRODeck lists Heat Wave for these formats: Speed Duel, Duel Links, Common Charity, TCG, OCG, Master Duel.
A listed print of Heat Wave appears in Quarter Century Bonanza (RA03-EN058) at Collector's Rare rarity.
Among markets shown on this page, the lowest listed snapshot for Heat Wave is about $0.31 on Cardmarket (prices change frequently).
