The listing, One-month Xbox Live Gold Membership has ended.
This is from the Snickers Game Day Satisfaction Sweepstakes. I'm not certain if the same account could redeem more than one code so keep that in mind. I currently have 3 codes listed (all different all unused.) Go to https://account.xbox.com/en-US/PaymentAndBilling/RedeemCode?xr=shellnav to redeem. The winner will receive a digital code from me. I am unsure when these codes expire since the winning email never said anything about an expiration. Enjoy!