The advantages of private profiles are the fact they would not be widely used by all other botters around hence giving you slight more protection and safety to it.
As for how much gold, it would really depend on several things, here are a few I can think of:
How fast it will do everything the profile tells it to do?
Is the are open or closed? (closed as in dungeon, raid, etc/open as in an area that you would have other players around perhaps doing the same thing)
The combat routine in use
item lvl based on the place you are or what you're killing?