This trophy will require yourself and a partner over Xbox Live (Splitscreen will not work)
1. Launch the game to the main menu and start a party using
then invite your partner to the party.
2. Once they join you, select their name and press Square to bring up a menu, then select "Invite to Trade"
3. Once they accept your invite to trade a trade menu will appear, select the item(s) you are going to trade them, and make sure they trade something back.
4. Once you are both satisfied with the trade, press
and then select okay.
Boom Achievement Unlocked!