Online ad yes, not Craigslist though.
Not Hypalon. But it is in very good condition, and is air tight. Its been holding the same air pressure for over a week now in my garage. Couldn't be happier. I have been looking and looking for just the right price, and found it. I missed out on a couple others that crept up by not being around in time to buy it.
When one pops up that is priced well, go to see it QUICKLY, as it will get scooped up.
Or, don't be as cheap as me (lol), and grab a new one from Aquamarine in Richmond. I think its about $650 for the same size as mine with the airfloor from there. With a warranty and customer support. I took a flyer on mine, with no recourse.