Here is Sega Magazine from 1998, released only in Japan. Yes, Japan is quite a bit more attentive with their promotional items, and this magazine is a nice example. It has lots of content you would like if you could read it.
In the gallary is an example page with the contents. You can already see photos of Sonic items! Look at the ad for Royal canned something. Most of the ads just consist of some random person holding the item near themselves while someone writes on the bottom.
There are photos of some of the cool items available at the time. The magazine seemed to be here to inform the fans of what great stuff they could get. (What an idea! Why can't USA Sega do this?) It probably even says where to get it. Notepad, bank, shirts, patches, a tie, pencils, keychains and a mysterious disk top off the selection.
https://sonicdistrict.com/merchandise/magazines/2546-1998-sega-magazine#sigProIde30b558205
In this gallary is a cool interview with Sonic Team! What kind of interesting info and opinions could be revealed? You can see photos of the game boxes, but you can't read any of it, it's all in Japanese.
"Page Jack": a sort of fan-area for people to write in to. As you can see, there's Sonic the Hedgehog, Espio and NiGHTS fan art, along with little Sonic tidbit images and possibly info or letters.
"HUmar from PSO": Look at this guy. This looks like a HUmar from PSO. The hair is almost exactly the same. Want to enter the Twilight Zone? He's from 1998! That's YEARS before PSO even THOUGHT about existing. Maybe it copied him.
Additional Info
- Region: Unknown