This is a completely free flashlight application that uses the LED on your device's camera as a flashlight. If your device does not have a camera LED, it will paint a white box on your screen to enable it to serve as a poor substitute for a flashlight. When I say free, I mean no ads. The app requires the Camera permission to control your device's LED but you will notice that it does not require the Internet permission as it serves no ads.
This is an open-source project (GPL v3) - you can see the source at https://github.com/abitsinc/AB-ITS-Inc-Flashlight-Android .