I'm new here also, I bought a 1984 31' Airstream last Jan, a fixer-upper. Anyway, it was missing a screen door, after some searching on the internet I didn't think I'd ever find one and/or could afford. A few months later looking for something else I saw an ad where a guy was parting out an Airstream that was involved in a accident. I emailed him asking him if he had a working screen door. Long story short; yes, $150.00 + $100.00 shipping. I received the door three days ago. Needs a little work but as a retired Boeing mechanic I'll make it work.
Keep your eyes open, you'll find one without paying several hundred $$$.