Just about any ad on FB is a potential scam, sadly. Especially when the price is too good to be true. And FB does not care. They come in waves, the counterfeit US postage stamps, the "Louis Vuitton" going out of business sale. Unless the ad is from a company you have heard of, like Kohl's, be very careful. You can look up the website of the business to see when it was created (google Domain Age Checker). One that was created a few days ago is likely a scam.