Here's a regularly updated framework from R.J. Dial - Price vs. Condition - Airstream Values
. The high end of the price range would apply to a well maintained unit in close to original condition. There's a cuteness & small tow vehicle allure to Bubbles & Caravels. Demand is high and supply is low. It's like lakeshore -- they aren't making any more. Price comes down to what the next one sells for -- or what somebody else would pay to jump in on your deal. But I think the above would be a good reference if you're trying to be fair and relatively up to date.