Jose wrote:

So as a private pilot [licensed and operating outside the USA], I am not
allowed to offer flights to the public. Even not if I ask less money than
their share. On the other hand, I'm allowed to fly with a friend, even if he
pays everything and the lunch. The idea is, that the reason of the
commercial ticket is to protect the public. Makes much more sense to me.

That's the way it should be. Here in the US we've muddled things up.

Define "friend" for us NG folk. Now define "friend" in a 'legal' sense as
you would like to see it written in the FARs.

Hilton