In the DS version of Final Fantasy III (if my friend arcanedude34 hasn't already said this) but I found a way (accidentially) to duplicate items (very useful for elixers, phoenix downs, anarctic wind, etc.). First, make sure the item you want to duplicate is on the top row of the item list. Then get into a battle. In battle press items and when you have the cursor over the item you want to duplicate you press A (or the button that's to the right) and the directional "up" button and if you do this correctly this will duplicate your item.
