Value of Doll

Hello, I acquired a doll that just caught my eye for some reason. She just seemed unique to me; especially the large windup key in her back. I had someone tell me that her face and hands are bisque and not porcelain. I'm not sure about her feet as I'm afraid to take her shoe off and check because she seems so delicate. I am attaching pics of her and was wondering if you may be able to tell me anything about her. She plays a song which I am not familiar with. Just curious as to if she is worth anything or not. Any information you may have or could find out for me would be very appreciated and interesting. Thank you,

Good