nwm50,
If you don't have one, do yourself a favor and go to Singer and download a free owners manual. Print it so you can have it with the machine. The controls on the 401s are not overly complicated once you get used to them, but they are not intuitive. You must set the stitch pattern knobs in the correct manner or you'll jam up the machine. The owners manual gives specific directions on how to set them so you get the best use of your machine.
Also the manual tell how and were to oil and grease them. Very important for this design of Singer.
As for the machine fetching $400.00 ..... no way around here. Maybe in FL if it's in mint condition with everything, but it won't sell for that anywhere around my area.
Joe