Once you get your airship, head to Daguerro (probably spelled that wrong haha) and notice how I had over 100k gil, now I have under 20k? Yeah, it is expensive to get the best gear, and you will need 2 of Zidane's newest weapons to create thief gloves, which hopefully was worth the 85k ish gil I spent to get them. Now, while you're going to Ispen's Castle, you will want to equip your weakest weapons, THAT is why I held onto their starter weapons this whole time. However! And this is VERY IMPORTANT! If you're looking to grind here, do NOT equip Zidane with his weakest weapon, equip the newest weapon (Sara) and have Add Status equiped/Soul Blade and you'll kill a certain enemy easily that grants nice AP and EXP ;)