You don't need to worry about it; Negrek will set it for you. It's the price you, as the business, pay for the service/product. So if the price the customer pays for something is $10 and the overhead, as determined by Negrek, is $6, then you earn $4.
In a mathematical form:
Profit = Revenue - Overhead
Overhead = Revenue - Profit
Simply put, it's the difference between what you earn and what the customer pays.
In a mathematical form:
Profit = Revenue - Overhead
Overhead = Revenue - Profit
Simply put, it's the difference between what you earn and what the customer pays.