The game gives you weapons slots and one warframe slot as you progress through the story quests. (One weapon for TSD, TWW, and Chimera, One Warframe slot for Sacrifice) DE historically have given out 3 weapon slots on each Warframe anniversery. There are occaisionally events that hand out a weapon slot. Last one was the relay-rebuild event. For Warframe on the PC, a GameFAQs message board topic titled 'does it give you free weapon slots if you receive quest reward items?'
Get a free starter pack of in-game items for Warframe’s Switch launch
Warframe Free Weapon Slots Event Games
Posted on November 19, 2018 by Brian(@NE_Brian) in News, Switch eShop
Warframe is celebrating tomorrow’s launch on Switch with a little gift. Players can receive a free starter pack of in-game items through the Inbox until December 4 at 11:59 PM ET.
Here’s the full lineup of rewards:
50,000 Credits
The legal tender of the Origin System. Credits are used to buy new Weapons and Warframes, but they’re also used to upgrade Mods — the primary source of gear power in Warframe.
3-Day Affinity Booster
With this Booster, all of your gear will rank up faster. As you play, your Weapons and Warframes will gain Affinity and rank up. Ranking up increases the Mod Capacity of an item, so you can equip those upgraded Mods.
Orokin Reactor
Immediately doubles the Mod Capacity of any Warframe. Install this Reactor on your Warframe’s Upgrade screen.
Orokin Catalyst
Immediately doubles the Mod Capacity of any Weapon. Install this Catalyst on your Warframe Weapon’s Upgrade screen.
Forma
When a Warframe or Weapon reaches max rank, you can choose to install a Forma on the Upgrade screen. Forma resets the rank of an item back to 0, but it Polarizes a Mod Slot to save on Mod Capacity. Forma is mostly used later in the game, but when you’re ready, it’s there for you.
In order to receive these gifts, note that you will need to complete Vor’s Prize in-game.