Rocket League has a large update planned for later this month, and has detailed more of the upcoming changes.
Rare items are about to be introduced. These can only be obtained by playing online matches, whereas the more common items can unlock by playing matches of any kind.
A new trade-in system will allow players to turn five duplicate items into a new item of increased rarity. Five uncommon items will unlock a rare item, while five rare items will unlock a very rare item.
Finally, Psyonix also announced their intention to implement a player-to-player trading system. As such, the developer is warning players to consider what they may trade-in, as items may have increased value on the open market with other traders.
Another reveal was promised for later this week.