Gil is something you will want in Final Fantasy X, although it’s not really needed too much during the main story. Once you reach the postgame and begin assembling customized pieces of weapons and armors, then you will be needed a lot of money. You’re not going to get super rich right away in FFX, as you will need to put in a little work, depending on the method used. There are three main options for grinding Gil in the game, with the first one being Mimics in the Omega Ruins.
As already mentioned, the first option involves the Mimics found in the Omega Ruins. Before you go there, you will need the Gillionaire ability on a weapon, and thankfully, Rikku comes with it on her Celestial Weapon. Mimics are random encounters in the dungeon, although they are disguises as treasure chests. Have someone use Steal on the chest and if it contains nothing, then it will turn into a Mimic. While there are four different types of Mimics, there’s no differences in terms of what they yield as spoils. Mimics will yield 50,000 Gil normally, which turns into 100,000 Gil if you have Gillionaire.
The only problem with doing this method is that it is completely random if you will get Mimics or not, plus the Omega Ruins can be quite the dangerous place. You will want someone with First Strike on their weapon, who also has access to Flee, since some enemies can ambush you and those aren’t the friendliest enemies in the game. That’s about the only real precaution if you happen to use the Mimic method.
One of the Monster Arena bosses in the game is named One-Eye, requiring you to capture at least four each of the floating eye fiends in the game. To grind for gil on One-Eye, you simply need to beat it in combat, so you might need to do some AP Grinding. Just filling out a good portion of the Sphere Grid (without adding any extra spheres) should be more than enough to defeat this flying foe. The catch with One-Eye is that the equipment it drops can be sold for more than it costs to start the fight. It costs 8,000 Gil to begin a fight with One-Eye, while the stuff it drops can sell from 9,000, all the way up to 67,000 Gil. Since it only takes two hits to bring it down when you’re doing 99,999 damage (Celestial Weapons have Break Damage Limit), you can do One-Eye pretty quickly and build up a nice stock of equipment to sell.
Kottos and Customization
The last method in obtaining a lot of Gil will require a little extra work on your end. Before doing this method, you will probably want armor with Auto-Phoenix on at least two people. It also helps to have Celestial Weapons and pretty high Strength to break the 9,999 damage limit. If you’re doing 99,999 per hit, then you are more than ready to do this method, but it isn’t necessary. To begin, you will need to head to Kilika and purchase any of the armors from the shop there (the Tetra armors). They cost 2,250 gil each and you can only purchase one at a time, so try to stock up on as many as you can.
Once you’ve purchased the armors, head over to the Monster Arena and begin fighting Kottos. He is quite strong and he will counter every attack, which is why Auto-Phoenix was suggested. If your damage isn’t too high, it is suggested to use Wakka’s Attack Reels or Tidus’ Slice & Dice (set their Overdrive Mode to Stoic for more mileage). Continually use the Overdrives until you defeat Kottos, making sure you Overkill him, as he will drop 40 Healing Springs. Use a Healing Spring to customize one of the above armors, turning that 2,250 gil piece of equipment into something that will sell for around 37,000 gil.
It takes 12 Healing Springs to customize SOS Regen, by the way, so you will need to battle Kottos many times to begin making bank. The biggest problem with this method is that once you customize all of the equipment you bought, then sell it, you will have to go back to Kilika to buy more armors. While this helps break up the monotony of the grind, you will have to travel to Kilika, then back to the Monster Arena, which can cut down on the gil grinding a bit.