I am going to look at a Singer 15 today. I have read on this board that people like doing FMQ with this model. How easy/difficult is it to do a full-size quilt on one of these machines and are parts readily available for it?

It's a very popular machine and I have not had any problems getting parts. The feet that fit my 6 year old singer fits it. (short shank) Enjoy your new machine.

looking for a picture of a model 1591 electric singer sewing machine.and how much is it worth? Thank you for your time.quilter65