Ahh, the Kantinegelds. Or 3rd Reich Canteen Currency. Long thought to be used as a kind of Canteen currency issued to the SS. It's been debated of their authenticity. Records are scarce at best. Wether or not these really existed or were produced as a novelty items, there are 2 variations circulating. One way more than the other...
Above left is a Brass example. Nice natural looking patina with a really smooth and beefy edge. If I was to guess, it looks genuine and to be the real-deal.
Now, the knock-off to the right of it. I believe it's made from aluminum or zinc. It feels flimsy, the edge thickness/width varies from coin to coin (I've got a few I've been stuck with). There's also several dead giveaway's...
1: The edge is not smooth. They looks hastily milled with a file or bench grinder.
2: Artificial patina (fig. 1) above. Yuck. The other one was worse so I cleaned it with Brasso.
3: On the side with the SS, in the lower right quadrant (fig. 2) there's a light pit.
4: Lastly, there is a raised dimple (fig. 3) just off the edge of the 5 of 50.
The Brass one, for all appearances, looks struck. The fake looks cast, which makes sense why the edge is all crappy. They had to clean up the seam.
I've seen the Brass one's go for upwards for $200. Even if those are novelty items, they are pretty nicely made. The counterfeit one's should not be sold for more than $10 and be advertised accordingly.