I know this has been asked a zillion times and there are many search results all over the web. However, I have never found any answer that actually fixes the problem.
So, to restate: I have an iPhone 5C (model 1532) with 8G (says 5 available). I'm running IOS 9.2.1. My storage says I have 0 bytes available, and I can't do anything that changes it. I've tried a reset (power+home). It says I have 180M in photos, however I did go delete a bunch and the number didn't change. I don't have iTunes, it's not connected to a PC, I don't have music or videos on it.
How can I free up space? How can I delete files (pictures, apps) and have the system acknowledge the change? This is seriously frustrating that I can't manage the space usage on the device.