You’ll need to import it
A long long time ago, before some of you were born, people practically trampled each other for anniversary Sonic merch. I mean the little blue guy still can whip up a consumer frenzy every now and then, but the 10th anniversary pack bundled with Sonic Adventure 2 was something else. Sold in limited quantities as part of 2001’s Sonic Adventure 2 rollout, the pack ended up becoming super rare. For reference it came in a really cool box, a soundtrack CD emblazoned in tacky gold coloring, and a factoid booklet.
Segabits explains the snap-in-time anniversary situation perfectly, while telling us how we can all rectify this mistake. And if you weren’t born yet, why didn’t your parents buy you one preemptively to present to you as a family heirloom?!
The 10th anniversary pack
We’re since long removed from the “10th” celebration, and now Sonic is entering adulthood with the “Ultimate 30th Anniversary pack.” As Segabits explains this one will be an import-only affair, but it doesn’t seem to be as insanely limited as it once was. As you can tell by the image the CD, coin, and book are still intact, it’ll just come with Sonic Colors Ultimate instead. You can grab it off Amazon (PS4/Switch), the Ebten Sega Store (PS4/Switch), or retailer AmiAmi (PS4/Switch). As someone who imports quite a bit, I’ve used both the former and the latter on numerous items. As Segabits points out, the Sega store option will require a proxy service such as ZenMarket, given regional shipping limitations. The whole shebang will run you roughly ¥9,889, or $90-ish US before shipping.
The DX pack
Or you can spring for the “DX” anniversary pack which comes with different goodies. It has a lunch mat, wall scroll, a pouch, a bag, an acrylic stand (of Eggman, his robots, and the captured wisps) (PS4/Switch). That one is only on the Sega store. Good luck!