As part of our Multi-Currency functionality, Enterprise users can select a selling currency when setting up a new project.
To do this, simply create a new project and select the selling currency from the dropdown menu titled "Currency".
Note that the exchange rate is locked in at the time the project is created. For this reason there is no way to change the selling currency once the project has been created.
For more information about setting up your default purchasing and selling currencies, click here.