I was exposed to those ugly guns by a friend of mine and darn his hide he never would sell me any of his collection. But I kept my eyes open and I now have 5 or 6 of them. I think, I haven't had any of them out to the range for 10 or 15 yrs. As far as value goes they vary all over the scale. Some that are rare go for many thousands of dollars. Other ones that are in poor condition and made by other countries (not Germany and the Mauser Factory) can be picked up for 200 or 300 dollars. There are a lot of variations so if you plan on collecting them you better win the lottery. Enjoy.
PS there is a good book about them called System Mauser by John Breathed and Joseph Schroeder A pictorial history of the Model 1896 self loading pistol.
Yes it was called "Snell Fure" or something like that. Clint Eastwood had one in one of his spaghetti westerns. Very few were made and of course they are a machine gun. The real rare ones were chambered for 45 acp. They are big and beautiful The .30 Mauser is the normal caliber but there were some chambered for 9mm Luger too.