Redeem a free Premium code

Redeems a code for free Premium on your Personal account, such as 6 months of Premium with no card. An account already paying through Stripe gets the free months after its paid period, with nothing charged; Stripe bills again by itself afterwards. A code is single use, and an account gets each offer once; repeating your own redemption answers the same. An unknown, used, revoked or expired code, or an offer the account already had, is invalid_code; five of those in an hour wait an hour (redeem_throttled). While a free period runs another code is promotion_already_active and stays unused.