If one paid 30,000, one could become a permanent resident of Soaring Cloud City. However, one could only stay in Area C. If the residents of Area C did not have special abilities, they would not be mutants or scientific researchers. They would not want to become soldiers either. They would have to spend 30,000 to enter Area B.
There were many ways to accumulate wealth. The most profitable way was by hunting monsters. In the Soaring Cloud City, beasts above the Rare rank were called demons. A Rare-ranked demon's body was entirely a treasure, while soul gems were more valuable. The machinery core of the Soaring Cloud City could turn soul gems into energy. A Rare-ranked soul gem could sustain the daily consumption of the walls of the Soaring Cloud City.
Of course, soul gems could not be consumed so easily. These gems were very precious and needed to be used at critical moments.