I'm reading the history of coffin making while I wait for my little wooden coffins to be delivered next week. I want them to be as authentic as I can get them in detail.
In reading, I found out that most states require an "alternative container" for cremation. It's basically a rigid cardboard box. Some are nicer than others, and are usually sold by funeral directors for $100.00 to $400.00, depending on how nice they look. The body has to be cremated in this box, by law.
If the body will be viewed, or needs to be carried by pall bearers, another "alternative container" can be made of pine, or even be a woven basket. They're also cremated with the body. No metal can go through the cremation process.