"Ingame cash" is what we call the form of payment within the game. The currency is the diamond(s) and has the symbol
For your own game progress
For a recruit's progress. You can recruit a maximum of 3 players.
And last but not least, you can buy diamonds directly in the shop via PayPal. There are also various offers here.
In addition, there is the possibility of receiving diamonds for special services or activities directly from an administrator.