Fixed Price

In a Fixed Price billing model, the tasks you undertake and bill for are for a fixed pre-defined price. When you opt for this model, the ‘billable’ option for expenses and time entries in the project is not checked, by default.
To see the value of Fixed Price, click on the Advanced tab on project.
As an example, you may decide to paint a wall for a fixed price of say 20k, so the billing is fixed irrespective of the number of hours spent on it.