Received an email from Microsoft with this promo. Text MICROSOFT to 29502. Can use online or in-store. Couldn't find any restrictions but seemed to work on xbox one bundles including Sunset Overdrive and new CoD ones.
Link to sign up online
https://microsoftstore.promo.eprize.com/mobile/?WT.mc_id=PromoEmail_SeptemberNewsletter_OnlineBM_9-12-14_Hero_SMS_S3
Link to sign up online
https://microsoftstore.promo.eprize.com/mobile/?WT.mc_id=PromoEmail_SeptemberNewsletter_OnlineBM_9-12-14_Hero_SMS_S3