Welcome to the Vintage and Antique Machine group of QB. My mom's machine would be pretty valuable to me... I hope you are wanting to get it back in good working condition and use it. I looked on the site where I find out the age and model # of Singer machine and didn't find any serial numbers starting with C. Could it be a G? If it's a G, it's a model 66 released in 1912. Value is in the eye of the beholder. I've heard of people paying little, a lot, or free for old treadles. Please take a picture and post it so all of us old machine collectors can oogle and drool over your treasure.