there is a pair of free codes on fanatical atm
https://www.fanatical.com/en/game/warframe-booster-pack-for-existing-players
https://www.fanatical.com/en/game/warframe-hikou-bundle-new-players
not sure how long they will be free for but figured i might as well mention it
i can't just post the codes as they seem to be single use codes generated per purchase but the items are actually free
and no multi purchasing unless you want to make multiple fanatical accounts maybe