WILD ARMS  

The trick below will give you 255 pieces each items.
First go to the item menu, then choose arrange to 
make the trick easier then go find some enemies.
When you're in fighting mode, the 1st character 
must use heal berry,
then choose defend for the second character. 
After that, for the third
character, move the heal berry to the item you 
want to increase, then
press the cancel button and choose defend.
When it's your second turn, again, the first 
character must use the heal
berry again. Find it. You'll notice that there's 
an empty place at the
top-left of the items screen . The second 
character must choose defend
again. And the third character must return the 
heal berry to the
top-left place, again hit the cancel button and 
choose defend.
After the battle, check your item screen.