This Code Requires 2 gba with link to do.

1st play a new game and get at least 2000 dollars or more. Then Save

Next Get the other gba to start a character. Play mutli and find the
traders bargain well. Use the character with the 2000 money or more
and buy until you ran out of room. Then look for what you want and
sell the rest. Keep on buying items and then trade all the good items
to the other player. Have the non-buyer save his/her game. the person
with the money shouldn't save. Quit the game and go back to it. Do
multi again with the same people you had. The person with the money
should have all the money and the person with the items should have
the traded items. Use the girl and boost the rare item
skill up and the use her to buy items.