He 'profited by' his experience/mistake. [=he learned something useful from his experience/mistake]
The book can be read with 'profit' by anyone who wants to understand how the system works.
We sold the house 'at a profit'. [=we made a profit when we sold our house]
(..) Yes. Then how did you know that Ms Qahraei gave her the number? Didn't she say it at the same time? OK. If we want to calculate the profit... Yes, I knew. Your mum was telling the truth. When they were talking in the hall, I heard everything from the kitchen. (..)2011 A Separation
(..) Go wherever you like. You still don't want to come? "He sells it for twenty a kilo. "If everyday he sells kilos..." Write . Then, how much profit does he make in one day? How do you solve this? Did you lie? What? Did you lie? (..)2011 A Separation