The special promotion applies when a person buys either the $399 Sonos Play:5 speaker or the $299 Sonos Play:3 product. Sorry, the $199 Sonos Play:1 speaker is not included in this deal.
The nice thing is that the Amazon buyer doesn't have to type in a special promo code or mail something in to get the $50 credit. Once the purchase is made, the amount will be automatically added to their Amazon's account seven days after the speaker ships to the customer. The credit must be used by December 31, 2014. But if you can't spend $50 on Amazon in the next six months, you might have an issue.
This promotion ends on June 14 at 11:59 pm Pacific time, so there's only a few days left to take advantage of this deal. The nice thing is that buying these Sonos speakers from Amazon still allows the buyer to also get the six month free trial for Google Play Music All Access. That promotion won't end until July 5.