So basically the only benefit you get for the fee is health care? Then its pretty expensive. Does it increase with income or is it a flat fee?

Can you work around the whole thing, if you make e.g. your wife (or father, or whoever) the owner of the company and hire yourself as CEO? So you would pay health care + other stuff as a percentage of your wage (which would be very low monthly + share of yearly profit).

I am asking extensively because I plan to spent a year in Spain in the near future. And while all this information is irrelevant to the stay (I am a student and will hopefully have set aside enough to spend the year without having to work on the side). But I really like to understand as much as possible on how the country works. :)