how to get the Point System on my site

[Dee30]

My friend made a site and i am one of the admins and i was wondering how do we make it so that everytime someone post something they get a certain amount of points for each post, and with those points they can trade or cash them in?
Edit:
can any1?

 

[FalseHope]

Is this a site or a forum? If it is a forum, then what kind of forum?