Cogs is one of the three skins released under the “Welcome to... Steamworld” part of the Steamworld offer. It could be purchased individually with game coins from late September to early October 2017.
Cogs could be purchased in the Skins Shop under the ‘Steamworld’ tab for 490 coins. This skin was available for a limited time and may not be available for purchase in the future.
Details of this skin can vary depending on location, platform or time.
Note: The “Welcome to... Steamworld” sub-offer with the Cogs skin was released again for a limited time in late December 2018. The price for the Cogs remained the same at 490 coins.