'03 31' Airstream Classic in good shape

I looked up my Trailer value on NADA web site and got a value of approx $14500.00. While looking at other sites, I see that this trailer has asking price of up to $30,000. How much are these Airstreams really worth? I am really confused as to what Airstreams are really selling for. Anybody shed some light on this subject?

Thanks,

Bob