In many cases the use of the service is provided by the city of municipality. Also in these cases new schools can sign up by leaving their contact information on the front page.
The yearly fee is 20€ per individual school. If several schools can be covered through the same fee the cost is 15€ per school.
Testing the service is free. Testing in this case means getting a user account, creating a questionnaire and filling it a few times to see how the service operates.