I agree. As a budget traveler, I'd love a service like AirBnB, but all of the listings are too pricey. If they targeted the frugal adventurers, I could see a community of such people developing around the site, and all travelers would use AirBnB, not just the richer ones.

While this could be painful in the short-term, it would help them achieve the ubiquity that they seem to want.