Just as a point of information, I bought a 1-year Netflix code on 30th January and received an email from them on 28th April: "Our records indicate that a Netflix Gift Subscription you redeemed was disputed and the payment for it was denied to Netflix. Due to non-payment, this account has been cancelled."
It's too bad I didn't post this 5 days earlier:
Be very wary of purchasing these gift codes. They are typically purchased with stolen credit cards or stolen accounts. Netflix cancels the subscription when the payment for the gift code is reversed.