Don't forget the basic science:
Not all light is polarised, so the main use of a polariser to analyse
the light will be lost. It will only act as a density filter, likely unwanted
at the time. For instance, a polariser will not do much for bright reflected
bright sunlight on choppy water. It
does help for other reflected
light off smoother water, cutting down on the polarised reflections to show
beneath the surface.
Anyway, good luck in your quest, and where it has been said to try for a cheaper
one first - sometimes it's useful to give vent to urges at the time - I agree.