Ptooti’s great window screen idea inspired me and I found two cheap and convenient ways to screen our bus doors as well.
The Snavely Instant Screen is a single screen that attaches to the top of the door frame and hangs over the doorway. It doesn’t seal tight like a rigid screen door but should keep out most of the bugs.
http://www.snavelyforest.com/shell.asp? ... endoor.com
The second one I found is the Phifer QuikScreen. It’s much like the Snavely screen except that it’s split up the middle. If you have dogs this one may be a better choice since they can just plow through instead of trying to figure out how to get past the single “pane” screen door from Snavely. Both run about $20.
I bought the Phifer screen (mostly because I found it first) and will do an update when I’ve used it for a while.