1. CLOSE RFACTOR (This is important)
2. go to the folder with your rFactor name in it, that is inside the UserData folder on your rFactor directory.
3. open the ANY_DEV_ONLY.cch file using a text editor (Windows Notepad for example)
4. In the top of it you'll find "Experience" and "Money". Change these parameters to a higher value.
5. Save the file with the same name and run the game normally.