Some overview of an ATO in Germany.
25€/flyinghour VFR PPL. same pay when "observing" soloflights. full pay during "RP"
42€/flyinghour VFR CPL, IFR SE/ME & SFI
no retainers.
The system worked like if your student was satisifed with you, you will get him for the next seesions again. Summarized a student had about 2-3 Instructors going with them until the exams.
I had about 5 flying hours per day plus 3 unpaid hours for briefings at 5 days a week.
my income was indeed quite good (VFR PPL and after 200 hours CPL) but it was hard work if one's doing it in a proper manner.
For me the personal development and skill boost was extraorbitant. Don't do it just for money. Your students will notice
Good luck to you