Thank you to Jeff Lemanski for a link to some kosher socks. You can buy 100% cotton socks, without elastic or any mixed thread, from a company in the United States. And, unlike the expensive socks I've found before, these are only $2 per pair. The pure wool and pure cotton socks I located before were $45. To get your fix of kosher socks at great prices, here is the link: The Railroad Sock — non-elastic kosher work socks
In a pinch, you can get 100% nylon socks for $1 per pair at a chain called Payless Shoe Source. I don't see anything in Scripture against wearing synthetic fibers. Payless was the only place where I found socks made of unmixed synthetic fibers. Human beings emit electric fields. Some people call them "auras". You can view a persons electric field with Kirlian photography. The healthier a person is, the larger their electric field. People who wear lots of natural fibers tend to have big electric fields. People wearing mostly synthetic fibers have almost no electric field. That isn't hard or scientific, but it is good enough for me. I'll avoid synthetic fibers where possible.