In reply to Darkskys:
It's not worth very much at all, sadly, especially if it is one that is in a box as opposed to a treadle. Even treadles in good nick might only raise £50. But try not to dump it- put in in the yellow paper (stuff for sale) or preloved or something so it can go to a good home.
Sxx
(I have a lovely Singer treadle, used to have a Jones hand turned m/c)