If Google Drive displays a "Quota Exceeded" or "Download Limit" message, try creating a copy of the file in your own Google Drive account (Right-click > Make a copy) and then download it from there. Alternatively, use the "Add to My Drive" feature.
After following this guide, you should have:
Apple never released Snow Leopard as a free public DMG. The official versions were:
To download , you must distinguish between the full retail installer (needed for a fresh install) and the 10.6.8 Combo Update (used to update an existing Snow Leopard installation). Official & Safe Download Options
A: Yes, but you’ll need TransMac or a similar tool to write the DMG to a USB drive for Mac booting.