He hadn't 'bargained on' how his new position in the company would change the way people treated him. [=he was surprised by how his new position changed the way people treated him]
You're allowed to go to the football game tonight, but I expect you to 'keep your side of the bargain' [=do what you agreed to do] and clean your room.
They've agreed to turn the land over to the state, and the state, as its part of the 'bargain', has agreed to keep it undeveloped.
(..) -That will be all, Michael, thank you. Aringarosa. Silas has succeeded. The legend is true. It hides beneath the Rose. My part of our bargain is nearly fulfilled. I meet the council in an hour. I will have your money tonight, Teacher. The Vitruvian Man. (..)2006 The Da Vinci Code