German States stamps are synonymous with classic philately. Before 1870, what we today call Germany was a confederation of numerous independent states, ten or more of which operated their own postal services and issued their own postage stamps. From about 1850 on the German states issued stamps, and even the earliest collectors vied for them as some of the rarest and most desirable stamps of the hobby.
German States collecting is fairly straight forward. The Scott catalog listing, which largely copies the specialized German catalog listing, is clear and concise and uncluttered with varieties except for the specialists. The Michel catalog makers (and German philatelists in general) have gotten collecting right. Germans (and especially German States collectors) can be among the most avid specialists in the world. German States stamps can be collected by shade and paper variety and perforation varieties on the later issues. There are fascinating cancellation studies possible. And the Michel catalog lists all of this. But Michel also understands that most collectors are not avid specialists, and if you make the general listings too daunting, you lose potential collector interest. 
So Michel lists all the different stamps as major numbers and varieties as varieties. This seems intuitive but actually is the German way of collecting, and though it has largely influenced the way Scott lists stamps and how Americans collect, this is not always the case (see my article on US stamps).
As Scott lists German States, there are (in all) several hundred stamps ranging in price from a few cents to a few thousand dollars. And German States stamp prices are very quality dependent—perfect, large margined specimens sell for about half Scott. Make the margins smaller or add a tiny thin and the price quickly dives to 10-15% of Scott. Thus a pretty complete, nice looking collection of several hundred different German States stamps in very nice (but not perfect condition) can be bought for under a thousand dollars. Forgeries used to be a problem, as packet makers and philatelic forgers in the late nineteenth and early twentieth century actively forged German States stamps (they were valuable, and because these stamps were superseded political entities, there were fewer counterfeiting laws to worry about). But time has been good to philately. There has been little reason to forge classic stamps in the last seventy-five years, and conscientious dealers have pulled most forgeries out of the sales stream.