This is easy. I remember one of my first forums i made was for me and my high school friends.
All you need is a credits add-on. Every time someone posts you would recieve 1 credit(1 penny). Later on after someone reaches 1$ they could withdrawl the money.
So you could send them real money via paypal.
After my friends withdrew their money, The next day at school I used to give my friends paper money when i saw them at school. Same thing!
I can't image actually giving people real money for every post. You would have to moderate quality posts. Unless you were super rich. Then it wouldn't matter.
AD Credits would work well. But i'm not sure if you can withdrawl money with his add-on. In fact i will ask about this feature. I know in *******'s you could.
Maybe i'll do this again and print out some cool looking fake currency! and mail it to members home. haha that would be fun... just like the old days..