When a map has the market available you have access to an additional building, the ‣. These buildings allow a trading spaceship to land with which you can buy and sell certain resources for dollars.

For every dollar spent or earned you increase your trader reputation. You can view your current reputation as well as market prices via the button in the top left. Once you reach the next reputation level you will unlock another ‣.

Selling resources allows you to create end points for your economies and lets your colony run forever. See how many dollars you can rack up!