in-game. Besides, in multiplayer, you can't search for RL Items individuals to exchange with outside of gatherings, nor is there a particular public space for that reason.
Rocket League exchanging: How to send a welcome.
In the event that you need to exchange with somebody, they should be in your Friends list. Then, at that point, either join their gathering or welcome them to yours, click on their symbol (found in the lower bar along the edge of your profile) and select 'welcome to www.lolga.com exchange'.
