Today’s comics sell one-tenth the numbers Marvel expected in the 1960s and 1970s glory days when comic books were cheaper than candy bars and just as easy to find at the nation’s newsstands, corner markets and drugstores. Now, a new comic book costs $4-$6 and the only shelves they reach are at the 2,500 comic book specialty shops doing business in the U.S. and Canada — and even that number is in decline as stores