If you want to convert a YouTube video into a playable MP3, then aTube Catcher works very well.
You just copy the YouTube link and then paste it into the downloader - then bang, for us, we just convert music videos to MP3 to make little car USBs to enjoy.
It can do alot more than that, but for me, it is easy to COPY & PASTE URL's.
But I do recommend in paying for content when you can.
I find that using YouTUbe to find songs, even songs that I know I have somewhere on a harddisk, cd etc, is easier timewise.
I'm trying the new ANDROID AUTO & I only have the choice of playing my USB or connecting my PHone - so now I've added songs to my phone.
Piracy
To me, copyright & protection has benefits and negatives.
1. Creators deserve revenue.
People need to earn money for their creations.
So, if you can afford to pay the curator, then do so.
2. Piracy creates followers
Piracy can be a form of marketing.
It can reach the eyes and ears of new fans. Fans are where the real money comes from.
An example, I had a song by Blue October on my USB, loved it, now I have multi paid albums, apparel & support their new albums when I can.
3. No money No honey
As per the reason above, young people may not have the money available to support all of their interests.
But, loyalty does pay in the end.
To be too stringent on copyright & creators may actually lose the attention of potential customers.
True fans will invest their time, energy and money to be part of the ride.
Enjoy!