^ I mostly agree with you, 75RR.
It is not cheap, but the other commercially available option (Chinese clone of Swift FM-31) costs $300. Neither of those have real condensers, standard objectives, filter trays or mechanical XY stage.
McArthur pocket microscope
may be available on eBay sometimes, but auction price would be difficult to predict. And I have never seen one for the past year (I did searches). Other options exist, but are even more expensive or rarer.
This kind of pocket
scope is useful in a pocket
or backpack (along with a slide and a few cover slips), when you are going to an interesting water body with family/kids, but not specifically hunting for protists.
I have a Meade ReadiView pocket
scope that provides up to 160x and reasonable images, but I want more magnification.
Last time I took my LOMO Biolam (~9 lbs) with my kids to a park. Since I also took camera gears, drinking water and other stuff, my belongings got really heavy and big..........
And sometimes when you use a full-sized scope in a park, people look at you like you are a mad scientist (though I am one
) or a bio-terrorist