Bukkit

Hello i want to sell the fly permission to users in my server. for exampel i want buy the flying thing and what the server does is that it issue a command for exampel /give fly {minecraft name for the person who purchased the item} and now i have the permission to use /fly to enable and disable fly
i use enji shop and is there a way to do this.

the enji shop lets me put commands to be used for example if the player purchase the fly or 100 dollar ingame money

i try using this permissionEX and other with essentials. its just to damn overkill for me :(

is this even possible? if not. pls help me im out of ideas to give fly permisson to players who purchased vip from my enji shop :(