This exploit can make 300k a day, first u need to bring smithing up to lv26, theres numerous guides on this but I found this to be the best one:
http://www.TAULTUNLEASHED RULES.com/2264.htmlafter your smithing is at lv26 you need to buy a composite rod and rouge rig, and you have to get fishing moghancement, once youve done that go fish for rusty caps. They can be found at the pond in S.Gustaberg in the funaroles, but the best place to fish them would be in the rabao oasis. once u catch enough u synthesize them into padded caps (light crystal+rusty cap), again this guide doesnt work for everyone, since the number of gil u make depends on ur fishing skill, but if its at least lv40 u can fish about 15 caps per hour. after synthesizing them into padded caps u sell them to NPCs for about 2k each, which means u make about 30k an hour.
*hope this is good enough for a premium membership*