Mark B. Ledenbach's vintage Halloween collectibles blog.

Antique Tin Germany Halloween Siren Whistle Witches Cats

This petite whistle noisemaker was made in Germany sometime during the late 1920s. Its RSIN is "2," so you know these don't surface much. Sustainable guide value is $150, so the opening price is actually not unreasonable. The whistling mechanism on these is often broken, so I consider it a slight bonus that this is purported to be fully functional. 
One negative with this seller is that the postage charge is $4.54. Given the item's small form factor and its negligible weight, postage shouldn't be more than $1.25, especially considering how tracking is now automatically included with First Class postage. 

06/11 Update: The buyer got a solid bargain when scooping this up for the pittance of $74.95.