..."rumors" say that as a ppl holder you can fly and "charge" someone only for the rental of the plane including the fuel....
I have also heard such rumours, said to be based on upcomming EASA rule changes, so I understand your thinking, but, as yet, I have been unable to find any such proposals.
So, good try Chrisonair.
For the moment, the basic rule is that, with a very few specific exceptions, if any valuable consideration is given, or promised with regard to any flight, then the Pilot must have a Professional Licence.
MJ