Trading is one of the features available to all players of Dune: Spice Wars regardless of which faction they chose. Players are able to trade their resources for other resources with other players—if they're playing in multiplayer—or with the AI if they're playing alone.
The trading interface shows all available resources that can be traded. Players can select which resource they wish to trade and what they wish to recieve in return, including the value. For example, players can chose to trade 10 plascrete, and can select how much of another resource they wish to recieve in return. Note that the bar down the middle of the interface highlights the likelyhood that a trade will be accepted based on the offerings.
Some factions are more willing to trade specific resources than others based on how they usually win the game. Players will not know if their trade is going to be accepted unless they confirm the trade—note that trades can still be declined even if the likelyhood bar indicates that the trade is a good one.