I went back to the estate sale this morning and I BOUGHT THE MACHINE!
I'm so excited. I asked and they came down on the price to $250. I had them set it up so I could try it out. I took some fabric scraps along just for that purpose. The stitch looked very nice, small, and even. It started out running a little rough, but it hasn't been used for awhile. It really needs a good cleaning and lube job. There was a buttonholer with it and more attachments than I know what to do with.
The little manal says it is a 221-1. The copyright dates listed are from 1915 to 1938. Does anyone have any insight on how that would relate to the date the machine was made?
Thank you everyone, for your helpful comments. I will be looking into the book you mentioned, Margo. If anyone has any more advice for taking care of and using my new baby, please join in!
(doing a happy dance in MI)