How many of YouTube's 1 billion monthly users will pay to subscribe to an ad-free streaming music service? It looks like we'll find out soon enough.

YouTube and indie music agency Merlin finally struck a deal to allow YouTube to license music from the thousands of indie labels Merlin reps, reports the Financial Times. And on Wednesday, YouTube announced that "YouTube Music Key," a $9.99 monthly subscription  that will allow users to listen to music and watch videos without being interrupted by advertising as well as to save music to listen offline, will launch next week, reports CNBC.

For months, the video-sharing website started by former PayPal employees and acquired by Google in 2006 had been in negotiations to license indie music from Merlin, a rights agency that represents 20,000 of indie music labels. YouTube had signed with Universal, Sony and Warner Brothers, but needed to sign a deal with Merlin, the so-called "4th Major." 

YouTube will enter a competitive market with other streaming music service providers including Apple Beats and iTunes, Amazon Prime Music service and Spotify, which recently announced that its total number of monthly active users jumped 25 percent to 50M in last six months. Midia Research told the FT that it anticipates that YouTube will make $500 million in subscriber revenue its first year.

YouTube Music Key subscribers will be able to access Google Play Music, according to CNBC, which also costs $9.99 and has access to 30 million songs. Google Play Music subscribers will get access to  more music videos and is rolling out a recommendation service based on listening habits that will be charted across Google Play and YouTube Music Key.