Unlocks at Level 2
Associated Task(s): Research costs
Cost: 3,000 coins
This building allows the player to sell excess materials directly to NPC Tradesmen. Once built, there will always be a Tradesman in attendance, who will make the player offers on possible materials in specific quantities. Each Tradesman will stay 6:00:00, and then switch to a new Tradesman.
The variety of items possibly asked for appears to be based upon the player's level. Meaning which buildings are possible to build by that level, and the materials that could be thereby produced or generated.
There are only 3 different Tradesmen, each with (theoretically) their own prices for goods, though there seems to be a small range on price for any given item, for each Tradesman.
Here are the three: