TennoGen is a collection of community created content that are selected by Digital Extremes and subsequently implemented in the Market. Revenue generated from the Market will then be split between Digital Extremes and the creator.
Latest TennoGen:Round 16 Upcoming: Round 17
The Warframe's Steam Workshop is a Steam library of community created items, where players can vote and discuss about prospective items to be implemented in game. Creations must be submitted via the official Steam tool Warframe TennoGen. TennoGen skins are purchased in the Market using conventional currencies via Steam.
Because any finances generated from these cosmetics are split between the creators of said cosmetics and the developers, players cannot buy these cosmetics using gifted Platinum.
There is some discrepancy for the number of TennoGen Rounds. After Round 1, DE held a Tennogen x Polycount Workshop Contest, which at the time was referred to as "Round 2". Rounds after it were called Rounds 3, 4, and 5. However, upon the release of what would have been Round 6, a post by [DE]Rebecca called it Round 5, despite the last round being called that as well. Older releases were retroactively referred to as Rounds 2, 3, and 4. Since then, all future Rounds follow this retconned numbering scheme, while the old Round 2 is referred to as the Polycount Round.
As of TennoGen Round 11, it takes about $829.00 to purchase all Steam Workshop TennoGen items. 49 helmets ($294.00), 22 skins ($110.00), 20 deluxe skins ($140.00), 15 weapon skins ($90.00), 3 landing craft skins ($15.00), and 30 syandanas ($180.00).