Starting at just $4 a month, Amazon's Echo music streaming service is the cheapest-ever option for commercial-free, on-demand music. Competing with apps like Spotify and Apple Music, the e-commerce company is upgrading its wares to include a monthly subscription-based music streaming.

The Amazon Music Unlimited streaming service comes at 3 different price packages depending on the consumer's budgets. The cheapest, Amazon Echo, allows users to play music on demand, but using only Amazon's Echo, Dot, or Tap speakers. If a user wants to listen to music on the go on their mobile phones, they must pay $10 a month for an ad-free experience on Amazon Music Unlimited. Users on Amazon's prime membership need only pay $8 for this premium service, another good deal coming from the e-commerce giant.

"In the last year, consumers have started shifting to all-you-can-eat music subscriptions in droves, but leading services like Spotify and Apple Music are absorbed in their race to win on the phone, where most of today's subscription listening happens," says CNET, "The cheap "for Echo" price and an emphasis on voice commands and are what set Amazon Music Unlimited apart."

Included in Amazon's music subscription is the entrance of new artificial intelligence assistant, Alexa.

"You can engage Alexa in a conversational way, which promises to be especially useful if you can't remember the name of a song or only remember some of the lyrics," says USA Today, "You might ask, "Alexa, play Green Day's' new song" and have it play Bang Bang, an example demonstrated to me. Or, "Alexa, play the song that goes, 'We ain't ever getting older.'" Alexa will play, Closer by The Chainsmokers."

With Amazon set to make a name for itself on the digital market of today, nothing seems to be in its way towards this new milestone. However, many are speculating that Google's "Google Home", also an AI assistant to be launched soon, could become Alexa's biggest rival.