
Research needed to build: Wealth (Economy)
Purpose: Used to buy/sell resources
Build in more then one town: Personal Choice, if you find yourself buying/selling a lot then yes as it opens up your target area to buy/sell.
Soft Cap: lvl 16 Can build higher but after 16 the cost is greatly increased.
General Information regarding the Trade Post
Lets take a look around the window from the Trade Post's view(once you click on your on the Trade Post)
On the left side of the screen you will see

Here you can see how much materials will be needed to upgrade and how long it will take. Also you have the option to demolish the building as well. Clicking demolish will give you a confirmation screen showing how much resource you would recover. This option is helpful for when you want to abandon a colony and recover some of the luxury resources and wood.
You will also see

This is an ambrosia feature. It allows you to turn one resource into another for a cost. Will be further explained in a Premium/Ambrosia Guide.
Below you will see

This shows how many resources you may have stored in the trading post at a time for sale.
Now in the middle you will see something similar to

Offers from trade partners--If you have a trade treaty with someone you will see their wares listed here. NOTE Due to a bug it is advised not to use trade treaties. They can led to resources disappearing.
Bargain hunter--This is used to find goods you are looking for, be it selling or buying.

Once you have picked the resource you wish to search for click

Clicking the


Here you can decide how much of the resource you wish to buy. Click

Now if you wish to sell resources, when you first click on your trading post, near the middle bottom you will see the following screen.


Enter the amount you wish to buy/sell in the amount column and then the price you wish to buy/sell for in the Price column. Note that the Price is per resource and not for the total amount.
Once everything is like you wish click on "Update Offer"
Misc
Range and capacity of your trading post are increased with every second expansion.