"Xbox.com has for its Gold Members (New & Existing): 1-Month of Membership for Free. If you are an existing member, you can extend your Xbox live membership by a month!
When you log in you will see the following offer: "Gold 1-Month Free Trial" even if you have an existing account.
If you have used this offer previously then you may not qualify again.
Note: If you do not wish to continue your membership after the trial then remember to turn off the auto renewal.
Thanks to Slickdeals.net for posting this."
Credit: Redditor GoGoGadgetReddit
I contacted them last week in regards to this offer. I couldn't redeem mine and it came up with a payment error. Turns out that I had previously redeemed the offer…..in 2012. Had a laugh at that one.