Is it the skill Coin? because i know the more u throw the more dmg it does.. u have to pay to do it.. but u dont wanna throw ALL YOUR money to massive dmg in 1 battle...because then your bankrupt...

The rewards that change accordingly? More you throw the more dmg u get and faster u kill but nothing for later.... Less you throw do lil dmg but u got money FOR later to spend

Doesnt relate to chocobos, its not technically "magic", and nothing to do with gold saucer. Doesnt require any MP to use... but it is a materia so not sure it fits when u said not use of MP OR Materia.