The process I use to validate a possible vendor is:
Is there a physical address on the web site? I use this for the next step in my validation process… I check the address provided in Google Earth to make sure there is a building there, and see what the surroundings are like.
Next check is a BBB look up on the information I have. Business name and address information. If they can not pass a BBB lookup, I am done with them, regardless of how good the deal looks. If they pass a BBB lookup, I then call the business. Usually a scam will give me the ‘Snake Oil Salesman’’ feel when I talk to them on the phone. Most don’t pass the first two.
That is how I do it. Your mileage may vary.