Details The plugins needed for the server. We need a plugin that will give you cash on kill. The plugin must have it so some ranks can get more than others. Also if you can add it so you cant boost. Why Making a custom plugin will get you - Donator - Beta Ranks. Donators will get double the amount of cash on the server and Beta will get to test new updates.
Plugin for getting money by killing mobs/players, but not more for each rank: http://dev.bukkit.org/bukkit-plugins/killspay/