I recently purchased a Samsung Galaxy Android MP3 player.
In addition to playing music and videos, it is really a tiny computer with the ability to go online and run many different apps.
At any rate, I keep my collections inventoried on various Excel spread sheets.
This device has a built-in app that allows me to process the sheets.
It was a simple matter to copy the files over and now I have my complete inventory with me when ever I hit the coin shows!