Margie:
Prices for vintage Airstreams are what the market will bear. Smaller ones (Bambi, Bambi II, Caravel) are more expensive. Of course the condition of the trailer and what YOU WILL INVEST in the restoration are the most important factors in pricing. A $6500 Caravel in pristine shape will be cheaper in the long run than the $3000 hunk of junk. These little babies can really nickle and dime you to death.
My 1968 Caravel weighs 2,500 pounds with battery. (I weighed it at a public scale last month). I think the weight printed in my owners manual, 2,300#, is a little optimistic.
Hope this helps
Jeff