Is The National Society of High School Scholars legit?

I got a postcard in the mail today from the The National Society of High School Scholars (http://www.nshss.org) and I’m torn whether or not it’s a legitimate program worth joining. It says you need to have atleast a 3.5 GPA to join, which I do, but I’m not convinced that it’s actually going to help me. You have to pay $60 to join thats why I question whether or not it’s actually a good thing to join or not. Anyone know anything about this?