Kama is the currency of Amakna. They are earned by defeating monsters, selling items and completing certain quests. Kamas have no weight, meaning a player can carry millions of kamas as easily he can carry ten.
The symbol for kama is styled K. Any NPC or other game price using K means kama. The suffix 'k' (short for 'kilo') means 1000 of something if it refers to an object. ('10k wheat' means 10,000 wheat.) When it refers to the currency, a k is used to represent normal units and double k ("kk") is used to indicate that the item price is --Thousand. For example, someone is buying a tofu feather for 20k. This means 20 kamas, whereas if he had said 20kk it would have meant 20,000 kamas.
However, If someone were to sell an item for '1.4mk' this would mean 1,400,000k. MK means Million Kamas.