Trading is the swapping of items between other Spaceships, using Cargo Ejectors to drop the items directly to the Spaceship being traded with.

Trader/Storage ships are found in all freeports, and they can be identified by the large numbers of items in stacks that they have and the large Expando Boxes, and sometimes have "Storage" in their name.

You can use a Comms Station to communicate to other Spaceships as well, asking to trade items.

Common Trading Items

• Flux crystals - They are rare and a must have for automation, even though stackable they are sometimes priced in item count instead of stack count.
• RC Turrets - Their rarity and usefulness make them of high value when trading
• Raw materials (Metal and Explosives) - They are very versatile and useful for a lot of things e.g. building
• Other rare items such as balls (volleyballs, beachballs, basketballs, and/or footballs).
• Loaders - Are usually traded often because they're used to make warships.
• Pushers - Another autoship construction item, and it's good for trading.

Notes

Also, see the Ship Design Guide.