These donut machines were popular back in the 1920s and 1930s. The company that made them marketed them as a money-making idea. They are pretty rare these days, but one occasionally appears for sale on E-Bay. That is the only place I know that one might be found.
As of 09 - 05 - 2011, I do not know of a Brown Bobby for sale. If you have one for sale, please e-mail me. I have people ask me quite often.