Platinum is an in-game currency which can only be bought with real world currency. It comes in packs of various quantities and they can be purchased on the Official Warframe Website (requires login).
It can be used to purchase Warframes, weapons, Equipment, sentinels, Mod packs, and other various items from the in-game Market. It can also be used to instantly finish crafting wanted items in the Foundry.
Additionally, for a short period of time, players could have upgraded their account with founder's packages. Not only does this support the developers, but it also rewards the player with hefty platinum bonuses at a much discounted price as opposed to buying platinum for cash from the market. See Founders for more information. Note that the Founder's program ended November 1, 2013. Periodically, bundles known as Prime Access are released that function similarly to the founders packages.
The game uses an optional payment system: almost all weaponry and Warframes can be earned in game (everything other than Founder-exclusive items and event, retired, or prime items). However, with platinum, the grind to obtain weapon and Warframe blueprints and their resources is circumvented. A player can purchase weaponry from the market for credits, although some weapons and all Warframes require the schematic to be purchased, and then crafted.
There are a few items that can only be obtained through platinum: Color Palettes, various Cosmetic items, Warframe slots, and Weaponry slots. Slots directly influence gameplay by allowing for a player to keep different weapons and Warfames in order to create different sets. If a player has filled all of their weapon slots he will have to sell one of their weapons/Warframes for credits and free up a slot or buy a weapon slot.
- One platinum is equal to 6.7 cents or 0.067 dollars. (US Currency)
- Platinum can be traded (besides the user's starting platinum) with other players for certain items or traded directly, with credit taxes. This is a very popular means of gathering platinum among the community. See the Trade System page for more information.
- When purchased using the Steam wallet or through the Steam client, the amount purchased with contribute toward finding a Warframe related Trading Card.
- Excluding the starting Platinum that all players receive upon signup, there is no way of earning Platinum in the game. The player must either purchase it with real world currency, trade certain game items to other players for said Platinum, or if the player is extremely lucky, obtain a meager amount of Platinum (along with a Platinum Discount) as a Login Reward.