I used to be a member of the "MBCOA" when I was a kid back in the late 70's. There was a sign up flyer inside T.V. Guide! Basically, you would sign up and select a kit from the add, and after that, they would send you a kit every month, I think you had the option of sending them back if you did not want them, but, as a kid, I just kept them! Most of the kits where from Revell and eventually they started sending out Monogram kits.
Revell had the Master Model Builders Club, that I believe later became the Young Model Builders Club, and that one you signed up with the flyer that came in their kits. It only cost a $1! You got some tools comprising of some tweezers, file, glue applicator, brush and some paints along with a certificate of membership, to hang in your room or club house, as they advertised, and a Revell Patch. Plus a newsletter with tips, the latest release news and a section devoted to Art sent in by members.
Both of them went away back in the early 80's and they are no more. Real bummer, it was a cool thing for kids back then.
And! I just found this! Good reading!!
http://www.ironmodeler.com/2011/01/revell-master-modelers-club.html