Apple Music launches today, and you can jump right in with a free, three-month trial. Individual user subscriptions will be $9.99/month thereafter.
The big question will be: How does it compare to similar subscription-based, streaming services like Spotify? MacRumors has a nice round-up of some early reviews here. From that article:
Everyone will be able to test out Apple Music for themselves soon enough, with the official launch of the updated music app in just a few hours at 9 AM Pacific. Those interested should remember to first download the new iOS 8.4 update an hour before in preparation for the streaming music service’s debut.
Get all the details at Apple’s page here.