I Googled "green singer 328k" and then clicked on images to get an idea of what this machine looks like. Not sure if it will work, but here's a link to what came up:
[Edit: I took out the link because it didn't work. Try Googling for yourself.]
I personally don't think it's worth $100 except possibly from a dealership offering a warranty with it. On the one-on-one market, I would think $50 would be the most it could be sold for......