Reporting time or cost over tasks will allow you to track the financial side of the project from the point view of real numbers.
Place your mouse over the task and click on clock icon at the right of the line.
You will see a window where you can enter hour rate / cost and also the time. When you enter both, the clock time is multiplied and your first report is in the world.
You can write a note or report it back to a specific date.
Reports as costs
You can also access the reports for the tasks as costs. Which is purchase material or pay a business dinner. You do not need to enter the time and you only enter the amount. Always keep the costs associated with the item they are related to.