Forty-two.
The first issue I remember owning was issue number 87, which was already part of the satellite era:

But I didn't actively collect the book (that is, seek out each issue) until about issue 106:

Which just happened to be the issue that Red Tornado officially joined the League.
Thereafter, I purchased nearly every issue up to and including 185

Meaning I was there the first time Hawkgirl joined, when Zatanna joined and even the time that the Secret Society traded bodies with the League (a major point in Identity Crisis).
I came back for issue 200

But after that, didn't really buy the book again.
So, with all that, you'd think a book full of fanboy wank for the seventies era JLA would be right up my alley.
Unfortunately, Metzler's overly talky, deriviatve, work is less a fun ride back to the League of my youth and more an sad exercise in watching someone clumsily exploit a shared childhood memory.