Stuckgear
The problem as I see it is that an FBO cost £X to run (property / staff / infrastructure etc) and will have Y movements / tonnes etc per year. So £X divided by Y + profit = the charge to each aircraft movement / tonne.
The problem is that as movements decreased over the last 2 years FBO's are having to take more per tonne / movement to get back to their original profit plan and are doing this by charging for services rather than increasing the handling costs. Add to this the ever increasing cost of security and you are looking a significantly higher charge that the "handling quote" received.
It is not that you are really paying €15 for WiFi, it's just that WIFI is being used as a vehicle to pay towards the FBO's overhead, just like in many hotels.
Phil