I discovered this while we were sorting out a friend’s house and have no idea if it is of any value although according to the web similar machines are for sale at fairly high prices. I suspect it must be well over 70 years old and perhaps encouraged her to become an accomplished craftswoman. 
When the Singer 20 toy sewing machine was introduced in 1910 it was in a league of its own. Although the Singer 20 was of a simple chain stitch design requiring just 40 components, it was very well engineered with a cast iron body. Compared to other toy sewing machines of its era, and indeed since then until the present, it is far more like a miniature adult machine than a child’s toy. When other manufacturers wanted to enter the same market, many decided to do so with a close copy of the Singer 20 and after WW2 several companies started to make toy sewing machines closely resembling it.