Half MP

Half MP, also known as Half of MP and Half MP Cost, is a recurring support ability that reduces MP cost by half. In some games, MP costs can be reduced to one using a similar ability.

Final Fantasy V
The helmet Gold Hairpin cuts MP in half.

Final Fantasy VI
The Gold Hairpin Relic cuts MP cost in half, and the Celestriad reduces MP cost to one.

Final Fantasy IX
Half MP can be learned by Vivi, Dagger, Quina, and Eiko.

Final Fantasy X
Half MP Cost and One MP Cost can be customized to any customizable weapon. Lulu and Yuna have One MP Cost on their Celestial Weapons.

Final Fantasy X-2
The Golden Hairpin accessory grants the wearer Half MP Cost, while the rarer Ragnarok bestows Spellspring, which is the No MP Cost ability.

Final Fantasy XI
The Scholar Job has two stratagems, Penury and Parsimony, which halve the MP costs of the next White or Black magic spell respectively. These are the first and basic stratagems, available starting at level 10.

Final Fantasy XII
The Sage Ring cuts MP cost in half. In addition, the Channeling Augments permanently reduces MP cost by 10% of the default value.

Final Fantasy Tactics
Halve MP, also known as Half of MP, is learned from the Summoner Job for 900 JP. All actions that require MP for this unit will have their costs halved.

Final Fantasy Tactics Advance
Half MP is learned by the Summoner, Illusionist, and Bishop classes by equipping a Light Robe.

Final Fantasy Tactics A2: Grimoire of the Rift
Halve MP is once again learned by the Summoner, Illusionist, and Bishop classes by equipping a Luminous Robe.