Couple things to help.
1) Most states have a free business search thru there Secretary of State, you can search for the business. Legitimate businesses can usually be found fairly easily.
2) Legit businesses also typically have an online presence these days, if on GB or anywhere else toss there name in google. Anyone trying to make a full time living in retail will have something, even if it's just a Facebook business page. Then use just there address in google and see what pops up.
3) search the address on google maps and look at the Street view, if it's an empty lot, you may have a fraudster
4) be weary of anyone who accepts digital currency as a preferred payment. Impossible to track down crypto fraud.