1. Warframe slots and weapon slots, etc are only obtainable via plat. However you can trade other players for their plat. All plat was bought somewhere other then the ones that were given away by DE or WF partners.
2. Unfortunately free Warframe slots are very few and far between. Your best bet to get a warframe slot would be to sell prime parts to get platinum to just buy them (at 20 a pop, it isn’t too difficult to make that up). Free (without spending any plat ever) slots come from the following.

Here you can see wich bosses are dropping wich Warframe parts.

The selected promo code will be pre-entered, and you will only need to log in and hit enter to claim your code. Each link will pop up a new tab, so go through and click every code you want before going through them all at the Warframe site. You can also enter there codes ingame. To do so, navigate to the Market while in your Orbiter. You can use warframe.market to find prices for most prime parts, which should get you a good deal next time you're in trade chat. If you don't have much in the way of prime parts, you can also trade Gold R5 Fusion Cores at 5 for 3p to start getting acclimated to the trading system.

Warframe Parts

Ash
Ash components are dropping from Grineer Manic Titan - Saturn from 15:25m
Atlas

Atlas components will drop from Jordas Golem.
Banshee

Banshee can be researched in the Tenno-Lab.
Chroma
Chroma blueprint will drop at the quest The New Strange.The parts will drop at the junctions.
Ember

Ember compnents will drop from General Sargas Ruk (Tethys/Saturn).
Equinox

Equinox components will drop from Tyl Regor (Titania/Uranus).
Excalibur

Excalibur compnents will drop from Lieutenant Lech Kril (War/Mars).
Excalibur Umbra

The blueprint for Excalibur Umbra is given to players upon completing the first mission of The Sacrifice quest, and the ability to build the Warframe is granted on completing the second mission. Unlike other Warframes, Umbra requires no further components and is constructed entirely from the single blueprint. However, even after being crafted, Umbra cannot be used until the penultimate mission. A second blueprint will not be given on replays.At the end of the quest, players will receive Excalibur Umbra at rank-30 with a free, pre-installed Orokin Reactor, and Warframe slot.
Frost

Frost components will drop from Captain Vor and Lieutenant Lech Kril (Exta/Ceres).
Gara

Gara's main blueprint will be awarded upon completion of the Saya's Vigil quest. Gara's component blueprints are acquired from Bounties at the 'Plains of Eidolon'.
Harrow
Harrow's main blueprint is awarded upon completion of the Chains of Harrow quest. The Chassis blueprint is acquired from Void Fissure enemies, the Neuroptics blueprint can be found from Rotation C vault on Pago, Kuva Fortress, and the Systems blueprint are rewarded from Defection missions on Rotation C.
Hydroid

Hydroid components will drop from Councilor Vay Hek (Oro/Earth).
Inaros

Inaros compnents will drop from the quest 'Sands of Inaros' (You can by the quest from Baro Ki'Teer ).
Ivara

Ivara's main and component blueprints are acquired from Spy missions (including Nightmare Mode) depending on mission level. Alerts and sorties do not reward identified caches therefore are exempt. All parts are in Rotation C of their respective reward tables, meaning they require three successful data extractions to be an eligible reward for the mission.
Loki

Loki components will drop from Hyena (Psamath/Neptune).
Mag

Mag components will drop from The Sergeant (Illad/Phobos).
Mesa

Mesa components will drop from Mutalist Alad V, blueprint in the market.
Nekros

Nekros components will drop from Lephantis (Orokin Wrack).
Nezha

Nezha research in the Tenno lab.
Nidus

Nidus' main blueprint is acquired from The Glast Gambit quest. Nidus' component blueprints are acquired from Rotation C of Infested Salvage (Oestrus, Eris).
Nova

Nova components will drop from Raptor (Naamah, Europa).
Nyx

Nyx's component blueprints are acquired from Phorid assassination missions during an Infested Invasion.
Octavia

Octavia's main blueprint is acquired upon completion of the Octavia's Anthem quest. The Chassis blueprint is rewarded from the Lua music puzzle, the Neuroptics blueprint is rewarded from Rotation C of Orokin Derelict Survival, and the Systems blueprint can be found in the A Rotation Cache of Lua Crossfire missions.
Oberon

Oberon's component blueprints are acquired from Eximus units. All Eximus units have a 1% chance to drop a component blueprints.
Rhino

Rhino components will drop from Jackal (Fossa/Venus).
Saryn

Saryn components will drop from Kela De Thaym (Merrow/Sedna).
Trinity

Trinity components will drop from Ambulas (Hades/Pluto).
Titania

Titania's main and component blueprints are obtainable from The Silver Grove quest. The quest is obtained from the New Loka leader at any relay.
Valkyr

Valkyr components will drop from Alad V & Zanuka (Themisto/Jupiter).
Vauban

Component blueprints are obtained exclusively as alert mission completion rewards.
Volt

Volt can be researched at the Tenno-lab.
Wukong

Wukong can be researched at the Tenno-Lab
Zephyr

Zephyr can be researched at the Tenno-Lab.
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Here you can see wich bosses are dropping wich Warframe parts.

Warframe Parts

Ash
Ash components are dropping from Grineer Manic Titan - Saturn from 15:25m
Atlas

Atlas components will drop from Jordas Golem.
Banshee

Banshee can be researched in the Tenno-Lab.
Chroma
Chroma blueprint will drop at the quest The New Strange.The parts will drop at the junctions.
Ember

Ember compnents will drop from General Sargas Ruk (Tethys/Saturn).
Equinox

Equinox components will drop from Tyl Regor (Titania/Uranus).
Excalibur

Excalibur compnents will drop from Lieutenant Lech Kril (War/Mars).
Excalibur Umbra

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The blueprint for Excalibur Umbra is given to players upon completing the first mission of The Sacrifice quest, and the ability to build the Warframe is granted on completing the second mission. Unlike other Warframes, Umbra requires no further components and is constructed entirely from the single blueprint. However, even after being crafted, Umbra cannot be used until the penultimate mission. A second blueprint will not be given on replays.At the end of the quest, players will receive Excalibur Umbra at rank-30 with a free, pre-installed Orokin Reactor, and Warframe slot.
Frost

Frost components will drop from Captain Vor and Lieutenant Lech Kril (Exta/Ceres).
Gara

Gara's main blueprint will be awarded upon completion of the Saya's Vigil quest. Gara's component blueprints are acquired from Bounties at the 'Plains of Eidolon'.
Harrow
Harrow's main blueprint is awarded upon completion of the Chains of Harrow quest. The Chassis blueprint is acquired from Void Fissure enemies, the Neuroptics blueprint can be found from Rotation C vault on Pago, Kuva Fortress, and the Systems blueprint are rewarded from Defection missions on Rotation C.
Hydroid

Hydroid components will drop from Councilor Vay Hek (Oro/Earth).
Inaros

Inaros compnents will drop from the quest 'Sands of Inaros' (You can by the quest from Baro Ki'Teer ).
Ivara

Ivara's main and component blueprints are acquired from Spy missions (including Nightmare Mode) depending on mission level. Alerts and sorties do not reward identified caches therefore are exempt. All parts are in Rotation C of their respective reward tables, meaning they require three successful data extractions to be an eligible reward for the mission.
Loki

Loki components will drop from Hyena (Psamath/Neptune).
Mag

Mag components will drop from The Sergeant (Illad/Phobos).
Mesa

Mesa components will drop from Mutalist Alad V, blueprint in the market.
Nekros

Nekros components will drop from Lephantis (Orokin Wrack).
Nezha

Nezha research in the Tenno lab.
Nidus

Nidus' main blueprint is acquired from The Glast Gambit quest. Nidus' component blueprints are acquired from Rotation C of Infested Salvage (Oestrus, Eris).
Nova

Nova components will drop from Raptor (Naamah, Europa).
Nyx

Nyx's component blueprints are acquired from Phorid assassination missions during an Infested Invasion.
Octavia

Octavia's main blueprint is acquired upon completion of the Octavia's Anthem quest. The Chassis blueprint is rewarded from the Lua music puzzle, the Neuroptics blueprint is rewarded from Rotation C of Orokin Derelict Survival, and the Systems blueprint can be found in the A Rotation Cache of Lua Crossfire missions.
Oberon

Oberon's component blueprints are acquired from Eximus units. All Eximus units have a 1% chance to drop a component blueprints.
Rhino

Rhino components will drop from Jackal (Fossa/Venus).
Saryn

Saryn components will drop from Kela De Thaym (Merrow/Sedna).
Trinity

Trinity components will drop from Ambulas (Hades/Pluto).
Titania

Titania's main and component blueprints are obtainable from The Silver Grove quest. The quest is obtained from the New Loka leader at any relay.
Valkyr

Valkyr components will drop from Alad V & Zanuka (Themisto/Jupiter).
Vauban

Component blueprints are obtained exclusively as alert mission completion rewards.
Volt

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Volt can be researched at the Tenno-lab.

How Do I Get Free Warframe Slots On Warframe

Wukong

Wukong can be researched at the Tenno-Lab
Zephyr

Zephyr can be researched at the Tenno-Lab.
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• All Warframe Guides!

You May Also Like:

How Do I Get More Warframe Slots

How Do I Get More Warframe Slots