The core is one color, coating another. Different sized cutting blades are used so that large letters have wider strokes and the edge of the name tag is beveled to frame the finished product. Metal tags are considerably more expensive and are probably not worth the extra cost. The metal is usually brass or some other soft material that comes with a plastic coating but still scratches easily. The vast majority of name tags and engraved signs are on plastic, some of which looks very much like metal, but wear better and are easier to work with.
Plastics engraving requires no special talent or extensive training.
One only needs to acquire a little dexterity, which can be learned in a few hours and a high school understanding of measurements and ratios. Engraving is a business that grows amazingly fast and has very little competition. It takes about 30 minutes for the average person to learn how to make a one line name tag, complete with cutting the letters, beveling the tag, and attaching the pin on the back. Turning out a name tag only takes a couple of minutes for an experienced engraver, especially when many are made assembly line fashion. Engraved plastic signs and badges routinely sell for ten to twenty times the cost of the materials because of operator skill, investment in the equipment, and the fact that there is not all that much competition.