I have never seen a copy of Sports Collector's Digest, but Wikipedia reliably informs me that it once had a key role connecting collectors and helping them to buy, sell and trade cards. Like all magazines, the Internet has hit it hard. At it's peak the weekly mag was over 300 pages, but more recent copies have had fewer than 40 pages. It also has its own website with price guides and so on.
But back in the 1990s, SCD also produced their own cards. They weren't licensed (as far as I can tell) and they were produced on rather flimsy card. Billed as 'pocket price guides' they were freebies to promote the magazine.
Card Number 522: Sports Collector's Digest, 1993; #51
The card design is reminiscent of those produced by actual card companies.
This card didn't cost me much either. It was an add-in on a purchase from my main card supplier, Gawain. It feels nicely ironic that it is still changing hands as a freebie bonus.