OK, this is going to be a unique/specific item to purchase, but it's great if you actually need one. Over 5-10 times cheaper than the proper hand held ones with a screen, though obviously this is more for the quick use without needing to pull out your real one.
It's basically an endoscope that you can attach to either your computer/laptop, or by using the Micro USB adaptor cable, you can use it on your phone with an app that you can download for live feed.
I got one for work, though my nephew loves to play about with it poking it around holes. Video quality is perfectly acceptable for most uses, though obviously not super HD etc.