Here I like to check
www.auctionzip.com for info on auctions. You enter your zip and how far you will travel and it pulls up auctions. They allow key word searches so I do featherweight, singer, feather weight, etc. and go from there. A lot of times there are pictures etc.
Here in the midwest, a price of $200-250 is a good range. Easy to get parts and a number are always at auction.
We also have a number on craigslist. If you use
www.searchtempest.com (fairly hard to use) you can check craigslist over a large geographic area. Hope this helps.