What is the value of a Pfaff 3.0 Select Sewing Machine?

I have a Sears Kenmore model 83 sewing machine cabinet style, model # 117831 and the patent # is 1646962. There are also these numbers on it E-6354 and 83X20205. I am not good with the compute so wondering if you could get me info. and it's worth on it.