Hello donnalynn -- Welcome to the forums.
The
Price vs Condition vintage website doesn't cover either trailers that new or the very limited run of 5th wheels. It does give you an idea of factors involved in pricing. You might monitor want-ads in the classifieds at this forum, the
Vintage Airstream Club or I think
www.airstream.com even has a classifieds area. At least look at similar length and year Airstreams & Argosy trailers to see what sellers think they're worth -- not always what they'll sell for of course.