A game, or mechanic in a larger game, where players make fairly open-ended deals with each other, usually for game resources. A key feature of a trading mechanic is DisparityOfValuation. 
- In Basari? Players negotiate who gets to take their desired action.
 - One of Bohnanza?'s only MeaningfulChoices is whether to trade or not.
 - The_Settlers_of_Catan? has resource trading as an important, but not the only, mechanic.
 - Pit? uses a frantic blind trade.