Never buy a laser cutter that you don't know who manufactured it
I really can't stress this point enough. If you see a deal that seems too to good to be true it probably is. When buying a laser cutter online or on the used market, make sure you know who manufactured it. There are many low-quality knockoffs out there and if it doesn't have a manufactures mark on it that's a pretty bad sign. Even when buying a Chinese laser cutter make sure it is a known brand or at least make sure you can really get customer service for it in the United States.