I picked mine up in London 5 years ago from Richard Caplan for the eyewatering cost of £60 [$100 approx].
But its ease of use means that it has seen a lot of service, especiallly when on the go.
I used mine only yesterday whilst on the Bangkok Skytrain, trimming the excess film with a swiss army knife, and was able to complete a load within a train stop.
When I mislayed mine some years ago a consequence was that my use of my IIIG declined until I found it again.
Valuable - very.
Essential - for me, certainly.
ATB
Rhodie