Although 48-hour free Xbox Live Gold trial codes are not available as of 2015, you can get a 30-day trial for the online service. It is not possible to sign up for the free trial if you already have an active subscription.
If you do not have a Microsoft account, create one first. You can create an account using any Microsoft service, including Outlook and OneDrive. Once you have a Microsoft account, sign in to your Xbox console using your email address and password. Agree to the terms, configure privacy settings, register an Xbox Gamertag and select an avatar to complete the Xbox registration.
Once your Xbox account is ready, sign into Xbox.com using a Web browser. Go to the Subscriptions page, select Gold - 1 Month FREE Trial, and click Next. Add your credit card and billing information, then click Next. Even though Microsoft asks for your credit card information, the company does not charge you until the trial ends.
You can cancel your subscription before the end of the trial to avoid subscribing to Xbox Live Gold. Cancelling the subscription before the trial ends does not cancel the trial itself. Microsoft offers three trials per console and one trial per account.
If you receive the 8C210007 error code when signing up for the trial, it indicates that either you entered your billing information incorrectly or that there is a problem with the Xbox Live service. Verify your billing information. If the problem persists, there may be a maintenance for the Xbox Live service. Try again in a few hours.