Player level determines the number slots available for workers, crafting and quests. Once the required level is reached, the player can pay gold to unlock the slot. Slots can also be unlocked before the required level is reached by using gems. Experience is gained solely by selling items to or buying from customers. Experience gain per sale is equal to roughly 20.534% of the base price of the item bought or sold. The base price is determined solely by the item's quality, and it is not affected by giving the customer a surcharge/discount or by having a price bonus from mastery progression.