Looks like it might be a Singer 128, I'm not 100% sure though. I think it's worth the money -at least from that picture. The bentwood case looks like it's in good condition and the decals on the body are intact. Looks like the shuttle for the bobbin is there, see if they still have the cover plates for it. My daughter's Singer 101 is missing the bobbin cover plate and it runs for $20 or more. I don't know what they would cost for yours. Other than that I'm guessing a good cleaning and oiling is most likely all it needs to run.
Looks like another bentwood case to the left of it. The seller may be selling more than one.
Rodney