Learning about the history of the game and I like stuff such as the Illustrated History of the NHL or McFarlane's Hockey History books (history of the NHL, Stanley Cup Fever, 100 years of hockey, etc).
I don't like more specific books such as the Sanderson one though The Game is cool. There was also a recent special magazine edition released by The Hockey News where they looked at each past NHL season and included some old THN articles in there.
I also found online 3 hockey magazines from 1955/56 called Hockey Pictorial. To get them, google Hockey Pictorial 1995 torrent and it should be the 2nd or 3rd result (torrent file).
I've found THN magazines online going back to 2009. I also found through my local library each THN issue going back to 2006 in pdf format though it's tedious to go through. They also have versions of Hockey Digest up there. If your library is in Canada then there's a very good chance they have access to the EBCO database or whatever it's called and that you can access these.
Anyways I'll keep searching for cheap hockey history books or any books online to learn about the game's past, might as well with a lockout. Martin Brodeur's book and a book called "How the NHL conquered hockey" are also floating online.