I bought a 1915 Singer 15-30 on Craigslist for $35. I didn't have a clue as to what I was doing. One time I had seen an Amish girl treadling and I thought it looked interesting. I took the entire sewing machine apart and cleaned each piece. (Thank goodness for digital cameras!) I also pretty successfully restored the cabinet that had water rings from plants and paint splatters from it being used as a work table during several painting projects. I learned a great deal from the project and I proudly display it in my home. There is a lot on great information on the internet and the members of this forum and absolutely wonderful and helpful.
And sewing on the treadle machine is a terrific experience.
Enjoy your search. I hope you have as enjoyable an experience as I did!!!
Colleen