This trick only works if you have more than one character
in your party. Go to a shop and choose an item to sell. Click
on it as if you were going to sell it. Then, change characters
to someone else in your party while you still have the item ready
to sell. Click on the character inventory to give them the item.
Then, click the item again and sell it to the shopkeeper. Stop
talking to the shopkeeper and check your inventory. The person
that originally owned the item still has it, and if you check
the shop you sold the item to, they will also have it. Note: Do
not return to the character's inventory that originally held the
item while still in the shop -- this will crash the game.
Strategy