This comic was available as a free insert in the following Marvel comics dated August 1999:
Gambit #7 (1999 series)
Generation X #54 (1994 Series)
Spider-Man: Chapter One #10 (1998 Series)
It was inserted between pages and could be easily removed. It was not bound into the larger comic.
It was also available via mail order with the other three issues from Kidz Water.