Is there a way to "Turn Off" My Magazine on Samsung Note 3?
The "My Magazine" feature is integrated into the Touchwiz launcher, so there's really no way to completely turn it off under Jelly Bean.  If you freeze/disable the app you'll see frequent crashes.

If you're still under Jelly Bean, you unfortunately cannot do what Robert suggests because it only applies to Lollipop.  However, the simple way to get rid of this piece of crap is to simply install say the NOVA launcher, or any other available in Google Play.