DRGM is often mistaken for a brand, but the initials stand for Deutsches Reichs Gebrauchmuster (see also it's predecessor: DBGM). and is some kind of 'copyright' patent protection mark, like a Utility Model. It is very similar to the patent, but usually has a shorter term -often 6 to 15 years- and less stringent patentability requirements. DRGM has been used from 1891 to approx. 1945
If you collect toys from this period, you have better luck finding them on the German eBay.
What's it worth? Take a look at this Drgm price guide: sold listings for a value indication.