Is there any way that I can increase my inventory without platinum?

[Athenex]

Im got frost and excalibur and I have Limbo and Oberon parts but I see I only have a remaining space is there anyway?

[Fendelphi]

You cant.
However...
You can get platinum by finding and selling Prime parts to other players. You can find prime parts by doing fissure mission(and binding a relic to you).
You get relics by doing certain types of missions(usually defense, survival, excavation and interception. In other words, missions were extraction is optional).

[^_^]

No. In any scenario it will cost platnium. You can be gifted a warframe slot if someone is willing to.

[Athenex]

ok

[✨Saint✨]

For certain special events, weapons are given as a present. If you have those weapons already you can delete the ones u already have creating some room.

EDIT

It should be pretty easy to get a few platinum for a warframe slot. Sadly there is no way to get a free Warframe slot as far as I know.

[Athenex]

but Im speaking of warframes

[Athenex]

should i delete excalibur? or stay with him?

[Dai]

Nope, but you can follow my recommended method below so you can get platinum for yourself without having to pay any money.

To start making platinum for yourself I would start by doing Vault Runs in the Orokin Derelict to get Corrupted Mods to sell. Vault Runs are easy and you don't really need to have anything special or be a high MR to do them, hell even an MR 0 can do them really. Well, I would watch this video on how to do them and where to get the stuff to be able to start doing them. Just be sure to get a group of people in recruitment chat with the other Dragon Keys. You can do something like H Vault Runs 1/4 (H = Hosting, LF = Looking For)

https://www.youtube.com/watch?v=sDDyiWnvtUs

After you get some Corrupted Mods then you can sell them on http://warframe.market/ (it's a great website for selling/buying/price checking things) which you'll want to make Sell orders (after you make an account on the website) and leave the website open while ingame. This is so people can message you while you're ingame to purchase your stuff. Then you can invite them to your clans dojo (you can invite someone to your dojo by going to the dojo then right clicking their name to 'Invite' them) and then use the Trading Post to trade with that person or you can trade with them at Maroo's Bazaar. Just be wary of the trade tax and your maximum trades per day (your trades per day are based on your MR) and you can only start trading at MR 2.

Once, you get the hang of trading then you can start farming for various prime sets then selling them on the Market for platinum, they normally sell for more than the invididual pieces separately. You can get the various prime parts from doing fissure runs and using relics or upgrade relics using void traces to get the specific parts that you need. A set being all of the blueprints or blueprint and the parts (if it is a weapon/sentinel).