Below I've scanned all 18 pages of the July-August 1971 issue of The Sport Advertisers' Journal, edited by Jay Knapp. This was one of several ragtag hobby publications that came and went in the 1960s and 70s, but this one lasted longer than most -- this was the third anniversary issue, as the cover tells us.
This issue is notable for including a column by 18-year-old Bill Mastro on page 6, the earliest hobby writing of his that I've seen, though it's entirely possible that there are earlier things of his that I haven't seen. Mastro lists all the baseball card sets that had come out so far in 1971, and announces "I guess you all heard I bought the T206 Eddie Plank card", that being the one he won from Dan Dischley for $320 in an auction in the June 1971 The Trader Speaks, as I posted about here:
http://www.net54baseball.com/showthread.php?t=218999. Mastro goes on to ask whether anyone has a Wagner for sale, but I doubt he got one from this article, since he didn't get his first Wagner until sometime the following year. He also has a "Wanted to Buy" ad on page 16 of this issue.
Among the other articles of interest is the one by John Kennedy on pages 10-11, in which he starts out by proclaiming that "Our hobby is slowly dying" and complains that the hobby gets no publicity. This is all part of his plan to get people to pay $1.50 a year to join his International Sports Collectors Association, one of numerous failed attempts in the 1970s to form a national sports collectors' group. It's interesting that Kennedy was so pessimistic about the hobby's future at a time when it was about to enter a major boom period, with the 1971 Detroit convention just a couple of months later (and the attendant publicity) being a major catalyst for that boom.
Sorry for the marginal readability of some of the pages; as you can see, this is dittoed, and parts of it are pretty faded.