if you want to become a miliionnaire in FF-8, here's my secret:

first, you must find a place where Mesmerizes are common (outside Shumi village).

next, you Mug them for their blades (that's if you have the Mug ability). you can mug 6 blades from them each time.

once you get 100 blades, you can convert 1 blade into 2 Mega-Potions with MedRecovery (i think), and once you have 100 Mega-Potions, you can sell them all for 500,000 Gil. you can get 750,000 Gil with the Sell High ability.