Thanks to @Vaseler for posting this on the Discord:
Level up and get into the action faster with this FREE Warframe Booster Pack! Includes:
- 3-Day Affinity Booster
- 3-Day Resource Booster
- 200,000 Credits
- And a Foxglove Syandana to wear on your Warframes!
These codes are only available on PC. You must have a valid Warframe account in order to redeem this free offer. Codes are valid until February 11, 2019. Codes are limited to a one-time use per account.
You just need to have an account, which is easy and free. Apperently they semi-regularly have rewards for other games as well.