As part of Amazon’s Alexa birthday celebration, they’re giving new Amazon Music Unlimited subscribers 4 months free for signing up. This is the first time Amazon has ever offered such a long trial period at zero cost. You do not need to be a Prime member to take advantage of this offer. You just have to be a first time subscriber. You might also need to own an Echo device to qualify, or it may just be that you need to have an Alexa-enabled device.