I too wanted a simple/quick (and cheap) solution to recording myself and my guitar during practice.
Here's what I came up with ...
At it's core, I used the Focusrite iTrack Pocket which was actually made for iPhones but then I sticky taped a block of wood to it's bottom to add a tripod screw. I also attached an old camera flash bar (screwed it to the wood block) onto which I attached an iPad Bracket. It all cost less than $100.
The great thing about this setup is that the Focusrite iTrack Pocket has both built in mics and a guitar cable input. It comes with free software for the iPhone/iPad that lets me select my inputs ... guitar cable and mono mic OR stereo mics and that app then handles the recording of both video and audio. It even helps by letting you add effects (room size), chorus, etc. or you can just save the straight recording if you want to use other apps to work on it. Because it is using the camera that is above the iPad's screen, you can see yourself while you are recording. In total it probably weighs a couple of ounces and the only cable is the foot long lightning cable that connects to your iPhone or iPad. The tripod connection is handy for positioning it in my practice room which tens to become cluttered. I just used a standard 1/4" tee-nut which I drilled into the wood to position it before I attached it to the bottom of the iTrack Pocket. There is an input level control on the iTrack Pocket, too. And this still works fine for my iPhone as well as my iPads.
Amazon sells the iTrack Pocket for $70 and that iPad bracket cost another $10.
Make sure your iPhone or iPad has the newer Lightning connector for charging it because that's how the iTrack connects to your device.
The app is dead simple ... tap the on screen record button and that's it!
One more thing ... it also improves FaceTime communication because it adds better sounding microphones.
Here's a photo showing it, below.