Rhapsody Deal? How does it work?

I admit I’m new to this, so anyone please fill me in, but how does this whole 30-day free trial with Rhapsody work.  Do you actually get to download as many songs as possible in 30 days at no charge?  I noticed somewhere else that you have to sync up your player with Rhapsody every so many days or something to that effect.  What if you don’t?  Is there coding in the music files that stops them from running after a period of time?  Do you ever get charged for them?  Seems too good to me, there’s gotta be a catch.  If there’s none, I’m ready to do some heavy downloading, but I have a suspicion it’s not as easy at it sounds…Help me out if you can.  Thank you!!

In addition if the license of the songs expired you will get an error msg please sync to continue your music subscription. It means that you need to renew the license of the songs.