If cheap shatterproof lens protection interests you at all, then check out my DIY video on YouTube.
This video would be useful to anyone wanting to make a transparent lens protector for scopes, cameras, binoculars, and more. The setup time is about 5 mins, and the materials cost should be well under $1.00.
The video is 18:33 long, so I split it into eight separate chapters. Most of the video revolves around testing the polycarbonate "Lexan" to demonstrate its surprising capabilities and real-life limits.