Copper

is a currency used within. It can be used to purchase various items and upgrades from The Desk, and upgrading the Composter.

is co-op soulbound and can not be traded between players. However items purchased with are tradable.

Obtaining
Varying amounts of can be obtained by completing offers from Visitors in.

reward is determined based on the amount of items requested and the Visitor's rarity, with this formula: $$Copper = \frac{\frac{BaseItems}{2000}}{ItemQuantityMultiplier} \times VisitorRarityMultiplier \times 1.3$$ where ($$BaseItems$$ and $$ItemQuantityMultiplier$$ are from the Requests formula) $$VisitorRarityMultiplier$$ is determined by the Visitor's Rarity:

SkyMart
can be used to purchase various items from SkyMart.

Crop Upgrades
Crop Upgrades increase the player's while harvesting certain crops. Each crop can be upgraded at the Desk for, and each upgrade grants. In total is needed to max out upgrades for all 10 crops.

Composter Upgrades
can be used to purchase Composter upgrades, which can be used to increase Compost production efficiency. There are 5 upgrade branches: Composter Speed, Multi Drop, Fuel Cap, Organic Matter Cap and Cost Reduction. is required to max out all composter upgrades.

Trivia

 * is needed to max out all crop and composter upgrades.
 * is currently worth if converted to Sunder I on the Bazaar.
 * Therefore all the copper needed for upgrades is roughly equal to.