A good deal of these postings with low prices are scams. I have no idea what they are fishing for if they do not return messages. I have found my van listed on a site called "Oodle" a few times. The pictures and text are from when the guy I bought it from's listing from a few years ago.
I've been trying to figure those scams out myself.
I think they only return messages to "buyers" that sound like good marks.