I have a number of vintage machines, with the oldest being from around 1900, most of which have been acquired here in California. I have found them on ebay, thrift stores, and yard sales, and most of them are VERY reasonably priced. With the attachments that came with the older machines, one can do just about anything a modern machine can do, outside of embroidery or fancy stitching. I've even seen references to "free-motion" embroidery done on a straight stitch only machine.
Keep your eyes open and keep looking. They're out there.