This article is from the Final-Fantasy and other Square Soft Games FAQ, by firstname.lastname@example.org (Nick Zitzmann) with numerous contributions by others.
It is possible to exploit a small bug in the game's buy/sell system to
get all the money anyone will ever need in a single quest. To begin
this, you must first save up a little over 10,000 credits.
In Koorong, you may have noticed that gold gets more expensive as you
buy it, and gets cheaper as you sell it. Well, there is one way to "beat
1. Go to Nelson (through Owmi, through Koorong/Kowloon). In one of the
stores, you can buy GoldIngots for the fixed price of 500 credits. Buy
as many GoldIngots as you can. Return to Koorong and sell them all.
2. Go back to Nelson and buy as much gold as you can with the additional
money. Return to Koorong and sell them, etc.
3. After a while of selling at Koorong, you will notice the price drops
as far down as 0. When this happens, continue to offer to sell **ALL**
of your GoldIngots (that is, keep pressing down on the controller to
decrease the amount of GoldIngots owned by your party in the Sell
screen). However, do **not** press the Circle button to sell them!
Instead, once you've reduced the price to 0 and are offering to sell all
your GoldIngots, begin to press up on your controller to increase the
GoldIngots owned by your party while still on the Sell screen. The price
will start to **rise**!
4. Continue to take back your GoldIngots until you have all of them
back, or until you reach the maximum price at 2100 credits, whichever
comes first. Then, start pressing down again to sell all your
GoldIngots. When you have 0 GoldIngots remaining in the Sell screen,
press the Circle button to agree to sell them. You will have quite a few
more credits than you started out with!
Continue to repeat steps 2 through 4 until you have over 50,000 credits!
At this point, you should stop doing this trick, since it will no longer
work reliably afterward.