When you create a project, you will want to set a profitability target -- and include that target in the project budget (for the project and for each hour of a person’s time). Resource Management shows only external rates for people and projects.
For example, your project has a budget of $50,000 with a 20% profit margin. Each person bills out between $75 and $150 / hour. These rates also have a 20-30% margin. That's the external rate billed, not the internal rate; your people can only have one bill rate.
Monitor how close you are to your profitability margins by keeping an eye on the budget bar on the left hand side of your screen; it shows how much over or under budget you are.