Google is offering a four-month free subscription on its music streaming service Google Play Music for new subscribers, allowing users to scan up to 50,000 songs from their music library.Typically, Google offers a 90-day free trial when a user signs up, but the offer has been extended by one month, the Verge reported on Sunday.Users can listen to custom radio stations on their computer or mobile device using Google Play Music service.However, users who use the free service face ads on their app, unlike those subscribers who pay around $10.Such users can also listen to over 35 million songs, download music to listen offline, and get access to YouTube Red.Though Google has offered similar deals in the past, it was not clear how long the deal would remain active.