I purchased my tire change tag from Bob G at about the same price as you mention, flawless quality. Now, if you look in the archives John L (thelews) gave the recipe to make one yourself on the cheap, including high definition scans. The result seems very nice, at a reported cost of 5$.
Many of the labels I found on the market left me wanting, especially the aluminum one in the trunk. Wrong material (mylar vs foil) shade, size, spelling, font....I am making it myself, and it will cost me a couple of hundred, whether I make one or a hundred.
I think the commercial vendors are not putting the "DB Teile Nr xxxxx" because it is Benz's property, some legalese of the sort.
All of this spending on cosmetics hinges on our respective level of mania. It can get pretty crazy, but hey, it's not as bad as a gambling habit!
Jerome