Hand Tools Archive
I have a metallurgical scope (the current cost would be about $550 or so) with camera. It's great for flat things, but less so for other things.
I also have hand held scopes ($<20) that are fine for inspecting edges when hooked to the laptop, but they are low resolution, low clarity, and as winston mentions, the lighting isn't really good enough for anything other than perfect situations - the scopes and their software don't do nearly as good of a job as a digital camera (like winston's setup) in determining what light is important and what's not, so any significant variance (and there will be a lot on a curved surface) is seen as a washed out bright spot and not much else.
A dissection scope (which is also top view rather than through the bottom view like a biological scope) could also be a decent idea if an eyepiece camera with enough resolution is available. The software glare limitation in expensive cell phones is really useful, though.
The cost of a replacement camera for my scope (the one it came with doesn't work with win 10) was $185, and that was one of the cheaper ones.
Winston's setup works pretty easily, too - holding a hand held scope can be a bit of a trick sometimes and after a minute or two with no decent pictures, time's up for me. The reason I post so many pictures with the metallurgical scope is just because it's really easy to use on flat things.