Spell Power Mastery 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, Spell Power Mastery is Unlimited.
YGOPRODeck lists Spell Power Mastery for these formats: TCG, OCG, Master Duel.
Spell Power Mastery belongs to the Endymion archetype—use that tag when searching for engine pieces and tech options.
A listed print of Spell Power Mastery appears in Structure Deck: Order of the Spellcasters (SR08-EN022) at Super Rare rarity.
Among markets shown on this page, the lowest listed snapshot for Spell Power Mastery is about $2.49 on Amazon (prices change frequently).
