There is a billing model for the use of Speech, Voice-Over and Subtitling that is based on your individual use of these functions.
You have a certain number of free minutes per month for these functions (the number depends on your subscription). This means you can have the respective minutes of content transcribed with Speech, dubbed with Voice-Over or subtitled. If you exceed this free quota, it costs extra every minute (the price also depends on your subscription). The resulting amount will be automatically charged to you or debited from your credit card or Paypal account.
To see how many free minutes you have already used this month and how many are left, go to MY SUBSCRIPTION via the ACCOUNT tab.
Here you can see in the usage overview, among other statistics, how many minutes you have used the respective function and how many you still have left.