So I had an iPhone 5 with an Otterbox Defender case on it, a good case for a birder and someone that drops their phone a lot! It also conveniently comes with a 'belt clip' (yes apparently these didn't go out of fashion in the early 00's!) so I realised I could make a phone scoping adaptor and still keep my rugged case on, I cut out a section of the belt holder so the camera wasn't covered and broke the clip off it. I then got a hard lens cap cover for my scope, easy to get one off eBay or similar if you don't already have a spare/hard version (a soft plastic/rubber version won't work as it has to support the weight of the phone)
I cut a hole in the lens cap and a bit of fiddling to line it up glued it onto the belt clip, giving me a detachable phone scoping adaptor allowing me to easily use my phone to digiscope with.
So if you already have a case for your phone and don't fancy spending £40+ then search for a belt clip for your case or get a case with a belt clip on it and you can make yourself a digiscoping adaptor for next to nothing!
I have recently upgraded to an iPhone 6 and got a Griffin Defender case, that also comes with a belt clip that I easily converted into a digiscoping adaptor
And to prove these do work and really simply, all you have to do is stick it on the end of your scope and start taking photos/video, here's a video I took using my homemade adaptor with my iPhone 5
Just remember to stop the video before you run like a mad head to wake up the lazy Little Tern Warden!