Profit - A financial gain, esp. the difference between the amount earned and the amount spent in buying, operating, or producing something. Salary - A salary is a form of periodic payment from an employer to an employee, which may be specified in an employment contract. Wage - A wage is remuneration paid by an employer to an employee. -- Source : Dictionary Wikipedia. Basically, I think there is no difference. It's like a Synonym. You still get paid.

profit = money that you gain by selling things or doing business, after your costs have been paid (a financial gain, especially the difference between the amount earned and the amount spent in buying, operating, or producing something) salary = money that you receive as payment from the organization you work for, usually paid to you every month (a fixed regular payment, typically paid on a monthly basis but often expressed as an annual sum, made by an employer to an employee, especially a professional or white-collar worker) wage (wages) is similar to salary = money you earn that is paid according to the number of hours, days, or weeks that you work (a fixed regular payment earned for work or services, typically paid on a daily or weekly basis) /Longman/Oxford dictionaries/

what's the DIFFERENCE...no differents