Someone should phone them and tell them it is underpriced and to list it for $20k to start and then work down from there.
Good advice! I initially posted it here to try to benefit my fellow Expo brothers. After reading your comment, I did think about contacting the seller today, but when I looked up the ad, the rig had already sold and the posting was down (no surprise).
I actually felt compelled to do just that with an older couple last year who were selling a very nice, low mileage, newer pop top camper van at a way too low price. It was a clear case where, if they’d left the price that low, a flipper would have snagged the rig and quickly reposted it for sale at a substantially higher price and been the one to profit. They took my advice, pulled their CL ad, and re-posted the camper at a price about $5000 higher.... and still sold their van quickly. About a week later, I unexpectedly received a very nice thank you card with a $50 restaurant gift certificate.
The surprising but heartening backstory was that these two had a small ministry down rural in Mexico and had used their van for going to and from, and camping in while visiting poor families in the countryside there. They were very, very happy to have been able to make the extra money and then put it to use in their ministry efforts...
But anyway, the point of my shared story is that sometimes when we see a deal like this, we can take the moral initiative and help out by advising another traveler when they’ve unknowingly and needlessly undervalued what they're selling.