We used to charge nothing for PPL exams for our own students,
At least you have that option. In the Netherlands, under the same JAR-FCL rules, even the RPL/PPL exams are administered centrally by the CBR, the same organisation that handles all drivers license exams.
Each exam is 95 euros (141 euros for CPL and up), you can only sit them in three locations in the Netherlands (assuming enough candidates per location - if not they may choose to send you to another), only at specific dates (five times a year), and before you apply you need to have a statement signed by a recognized and appropriate training facility that you are enrolled in the appropriate course with them.
Just getting that last statement signed and getting the approval back may take three weeks. And only once you have the approval can you register for an exam.