It's wonderful that you are re-energizing your great-grandmother's machine! With a little TLC, you'll have it sewing and singing, soon! As Glenn said, check on e-bay, and don't settle for the first one you see -- there's sometimes a lot of differential between the various sellers as far as price (and quality) goes!
Welcome to the Board. You sure came to the right place. This Board has many experienced, knowledgeable and helpful members!
Jeanette