Depends on what kind of wrestling you're talking about, what kind of location you have, how much money you have, and how crazy you intend to go when built. For "real" wrestling, as in the stuff you see in the olympics... a training mat is required. You can fake it with a two-inch thick layer of corugated cardboard, but to be honest it will only last for one match and your wrestlers will probably hate the way it moves. Still, if you're poor it does do in a pinch. You can buy the real athletics mat, designed for wrestling and martial arts, for cheaper than you can buy the materials to make one. Even cheaper is joining a local YMCA and taking a wrestling class. For high-flying, turnbuckle, "TV-style" wrestling, I highly suggest you build a bank roll and hire a sports doctor and an engineer, in that order. You CAN build a fake ring that looks convincing, and you could even build one that matches closely with your favorite TV shows design... but you cannot guarantee anyone's safety without detailed understanding on how the device works and why it needs to work that way.