Because you play as a trader yourself in , your reputation in the game is extremely important. In general, the higher your reputation, the more you can unlock in the game. As a result, it's in your best interest to increase your reputation as much as possible.
At the same time, when it comes to trading, reputation isn't the only factor to consider. You also need to be focused on, which is another important in-game mechanic that determines what you can and cannot purchase from the faction's vendors. As a result, reputation and Profit Factor go hand in hand, and you'll need to work on increasing both if you want to gain access to new items from the traders.
You can view both your reputation and Profit Factor on the left-hand window of the «Trading» tab.
You can increase your reputation in in multiple ways. Firstly, you can earn reputation by choosing the right dialogue options or by choosing to help a certain faction when the opportunity presents itself. While these do give a significant boost to your reputation, the opportunities don't come by very often.
Another way to increase your reputation is bytrading cargo to factions. This is done by going to the «Reputation» tab in the trading window. You can only trade cargo types, such as Provisions or Ranged Weaponry, once they're above 100%. Simultaneously,the factions must be interested in the cargo for you to sell it to them. As a result, make sure to check each merchant to ensure you're getting the most reputation in exchange for your cargo, as some vendors will pay more for certain types of cargo.
Colony Projects are the final, and arguably best, way to gain reputation with faction vendors. Colony Projects become available in Act 2 and provide both reputation and Profit
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