Impossible to evaluate without details/photos, of course, but it is probably priced between $400 and $1000 I would guess. No one can get closer than that without more info.
Production figures are by no means an accurate science, either. Serial numbers simply do NOT reflect the number produced by ANY of the firms who were licensed to make them (or merely put their NAME on them). The makers did not start with serial number one and continue numbering sequentially until end of production. Numbering system was shared by many makers, controlled by one authority IN MOST CASES (Simson/BSW being an obvious exception), allotted in some ranges, assigned as produced AS A RULE but NOT always in sequential order, and sometimes allowed to fall into existing numbering system of manufacturing firm when not a conflicting issue (i.e. Walther---for MOST of their production---NOT ALL) and can only be understood by examining the entire quantity of collected numbers from observed examples recorded. Data base currently indicates production estimates (in "ballpark" descending order) as: Mauser, Walther, Erma, Geco-marked (by all makers), and then a crap-shoot with Menz, the two consortia, and Simson mixed in with other makers. ROUGHLY. Sauer apparently assembled the Waffenstadt Suhl consortium guns, but did not mark any (observed) with their own logo, JGA made quite a few and contributed parts, Weihrauch assembled the Greenhearts AND made many both with their own name applied and for others who applied THEIR logo, Haenel contributed HEAVILY to production by others but only ONE is recorded with THEIR name on the receiver, and a handful of other small firms put out DSMs in very SMALL quantities in the first months of production. Confusing, isn't it? And that is the SIMPLIFIED version of it...
Geco did not make ANY of the DSMs they sold, but had them made by AT LEAST three of the firms who assembled the rifles. Their 1935 and 1937 catalogs promise their customers that they will "gladly supply a DSM from ANY OF A LINE of manufacturers" who DID make them. That is probably more information than you wanted, but it is all part of the very fascinating "big picture" of DSM production. Again, the numbers are VERY misleading, and overall production by ALL makers is almost certainly LESS than 100,000 total.
My nickel's worth of advice is: If you are wanting one, and it appears honest and in good condition at a price that is reasonable to YOU, grab it. Values are guaranteed to increase, as more is known about them. Any honest property markings or verifiable markings which make it unique can also add $$$ to its value.
Steve