ok here are a few good tactics for all who's short on cash... and i know that EVERYONE's short of cash becouse bribing is a pain in the butt <img src="/images/graemlins/laugh.gif" alt="" />
ok #1 tactic is very known... fight mimics (those boxes that dosen't contain items when you steal from them) that appear in omega ruins each fight gives aproximetly 50,000 gil so it's good if you'r low level <img src="/images/graemlins/smile.gif" alt="" /> also try to get the weapon custimization "gillionare" as soon as possible (rikku has it on her Celestial weapon).
#2 if you still haven't captured everything to the monster arena, get "designers wallet" (if you need help about how to get that item and how many you need to customize gillionare i'll repost here) and customize it to you'r "capturing weapons" becouse you'll realise that you get _ALOT_ of gil when capturing and well just double up the ammount and you'll se that from capturing one area (say mt gagazet) you could earn arround 500.000 gil... and that becomes one milion gil with gillionare... <img src="/images/graemlins/wink.gif" alt="" /> just a litle trick i used to feel that i acctualy got something while doing that boring capturing <img src="/images/graemlins/laugh.gif" alt="" />
tip #3 if you have unlocked "one-eye" in the monster arena... fight him over and over again and you'll get loads of weapons with the "triple AP" ability... sell those for 67.000 gil a peice eassy cash <img src="/images/graemlins/laugh.gif" alt="" />
tip #4 go to luca and buy armor or weapon (can't remember) well buy loads enyway and then go and customize 1 healings rpgin to them and you can sell them for loads of gil (i'll look more into this and tell you what items you need and how efficiant it is only read about it a few times) <img src="/images/graemlins/smile.gif" alt="" />
gl and hope this helps some