The really big difference in value to you is condition. Used trailers can vary widely. How heavy was its use and did they take great care of it. Or not. It's fairly easy to make these look good on the surface.
Is the plywood subfloor rotted, cabinets worn or damaged, all equipment working properly, filiform corrosion progressing along the exterior panel edges, under rivets, on fixtures, corrosion underneath? Get someone who knows what to look for on Airstreams to help you, they have their own issues.
The unmolested, pristine trailer is worth much more than one with serious hidden problems.
Doug and Cheryl
2012 FC RB, Michelin 16, ProPride 1400
2016 Ram 1500 Laramie Crew Cab 4X4 Ecodiesel 3.92 axles
The Truth is More Important Than the Facts