Denars make the world go round in Mount and Blade 2: Bannerlord. A great way to build up some money is by selling prisoners. It is maybe not the most ethical thing in the world, but might makes right in the world of Mount and Blade.
To sell prisoners, you must first get prisoners, and this can be done by fighting enemies. At the start of the game, you will be tracking down groups of looters, rogues, and bandits who are trying to steal various things and are hoping that nobody shows up to stop them.
After you see them on the map, engage them in battle, and anyone who survives the fight can be taken as a prisoner. To sell the prisoners, you will need to head for a major settlement. Smaller settlements won’t do, as they lack the infrastructure required to support trading people for Denars.
These settlements will appear on the map as large castles, and at the start of the game, you will want to deal with ones that match your faction. When you arrive at the Castle, select “Go to the tavern district,” and there you will see an option to ransom your prisoners.
This will get you a small amount of Denars for the people you have managed to capture. If you have taken a leader, or noble, captive, you should hold on to them until you can get a great price, or even use them to progress your own story. You will have the option to decide what to do with each prisoner or sell them en masse if you prefer.