Please comment only if you’ve had direct experience with this type of Facebook marketplace ad. They say that their prices are low because they are brokering repo machines. Of course, they want a wire transfer.
Ask a lot of questions, and tell them you want to actually see the item first hand, and will pay them on the spot if a deal is reached. And make 100 % sure it has been paid off in full by the seller, and get that in writing.