Final Fantasy X-2 is a video game in the JRPG genre that was made by Square Enix.
Use the following trick for easy gil, items, and experience. Before doing this, make sure you have a Lady Luck at a very high level (at least 85) with Random Reels mastered; have defeated Via Infinito; have the Highroad Winds Garment Grid; and have the accessory Admantite. Then, equip the Iron Duke (from Via Infinito) and the Admantite on your chosen Lady Luck and have the other two characters as Warriors. Have them equipped with anything that greatly raises magic defense, such as an Oath Veil.
Go to the last floor of Via infinito and fight Paragon. As soon as the battle starts, have your warriors use Sentinel and have your Lady Luck use Random Reels as soon as possible. Pause game play to make sure that you get all three sevens in the middle of the reels. This is important, as doing so will mean that "Congrats!" gets used first.
After this is done, wait. When "Congrats!" is used, Paragon will run off and you will get between 60,000 and 12,000 gil and between 1 and 20 Dark Matters (up to 30 if he is Oversouled). Once you get 99 Dark Matters, sell them to get just under 75,000 gil. Paragon leaves behind 9,000 experience points, and Dark Matters can be used to deal heavy damage on all enemies. Also, if you get an Alchemist and mix a Dark Matter with anything, it will make your party temporarily invincible.
To defeat enemies very easily, use the Alchemist Mix ability and combine a Holy Water with a Fire Gem, Water Gem, Ice Gem, etc. This will create a magic attack called White Hole which does about 10,000 damage to one enemy. To find gems easily, you need to rare steal from Flan Rojo, Flan Blanco, etc.
For easier Boss battles, you can use special Dress Spheres. With Rikku's Master Triple HP, Shell ,and Protector and Paine's Master Triple HP, and Scare, these abilities make it very easy to defeat Vegnagun and Shuyin.