I see them on Am a Zon for under 100 bucks,
Does anyone here have experience
with these?

Are they a cheap throw away toy?

I got one for some home project that I dont recall now what it was, and it was fine for super simple viewing in a tight space. The FOV is VERY small and it takes some wrangling to get the end pointed at whatever you are trying to get a closer look at. YMMV.

I have a bluetooth endoscope for looking in ears/nose/throat. It's the size of a pen. I find it useful, but won't shed a tear when my $14.26 expenditure inevitably breaks or no longer connects.

I bought this one 5 years ago and it still works great.

https://www.amazon.com/dp/B07C..._dt_b_fed_asin_title

I use it at work. Great for working in confined spaces where you can't directly see what you're working on. Or for finding that screw you dropped.....

It's definitely not medical grade quality, but for 26 bucks, it's good for what it does.

I used them extensively at work for seeing into places you can't see from outside the machine guarding to be able to what is actually going on.

Coupled with an iPad, they were one of the best diagnostic tools we had.

I bought a handheld unit for $120 on Amazon. I have used it a couple of times. My unit allows me to steer the camera head left and right and it is an absolute must have feature, but if I had it to do over again I would spend a little more and get one where the head can be steered left/right and up/down

I have one for inspecting the inside mechanical components.
Works reasonably well.