I liked this, it's a lot of information presented very clearly, about the differences, advantages and disadvantages of these various types of radios.
Also, he has an introduction to GMRS radios that is very detailed and thorough:
In the video he says the GMRS license purchase price was still $70 on the FCC website, even though the price had been lowered. But that's been updated since this video was made, I recently got my license there for $35.