The Thrifty Friend

You have known them as your penny-pinching peer, often attending social gatherings with them and always bearing witness to their meticulous bill-splitting. Their calculator never leaves their hand, and every coin is accounted for to the last cent. Today, during what was supposed to be a casual hangout, an argument about fairness in paying the bill sparked a rift between you both. Now, you wake up in a mysterious room, the door slamming shut with a message: 'You two must reconcile, or this room will be your permanent residence.'