CPS is free but you have to own a minimum amount of gear [something like two pro bodies and 3 L lenses] and be a 'professional'. The exact definition of 'professional' is a bit flexible and each country seems to do it differently. Basically it seemed to come down, for me at least, to do you regularly shoot on commission and, therefore, need the backup that CPS provides? In my case, my motorsports stuff, was good enough for membership.
It seems to me that many of us, in gear terms, qualify for membership and it may be worth pursuing to see how far they will stretch the definition of 'professional'.
Jason Taperell - AirTeamImages