Google's long-rumored music download service could launch within the next two weeks.

The music store will be an add-on to Google Music Beta, a free service that lets users upload and manage their existing music library in the cloud, "people familiar with the matter" have told The Wall Street Journal. Currently, access to the service is optimized for the desktop web and Android devices.

Like Apple's iTunes service, songs will be available as MP3 downloads for about $0.99 apiece. The company plans to leverage its social network, Google+, to drive sales. Users can share songs with their Google+ contacts, who can then listen to those songs once for free with the option to purchase a download copy.

According to the Journal, Google is unlikely to secure rights to sell music from two of the four major label groups, Sony Music Entertainment and Warner Music Group, which would inevitably frustrate users who are unable to find songs they might be looking to purchase. Other music services, including iTunes and Spotify, decided to delay their U.S. launches until they had signed agreements with all four label groups.

Sony is reportedly unwilling to sign because it believes Google doesn't do enough to stem piracy on YouTube and its Android operating system. Warner Music is unmotivated by the lack of financial incentive; Google Music is free and generates no revenue on behalf of the record companies — beyond driving sales through the downloads store, at least — while Apple's forthcoming music locker, a $25-per-year service called iTunes Match, will share proceeds with the record labels.

BONUS: Here's What Google Music Beta Looks Like on Android