is there a subscribe mod or is that something i just gotta add by myself?
Yes there is. But instead of linking you, and you most likely complaining because it is a paid plugin, i'll just tell you the easist way without paying is to use one of the donate plugins and then move them into different users groups after.
You mean subscribe as in a paid subscription or subscribe as in being notified when a thread is replied to? The paid subscription is a plugin and the thread subscription is built into MyBB, just click on the "Subscribe to this thread" link underneath the Quick Reply box.
yes i want the paid subscription
It is called MyIPN, but there is no free version so you will have to pay money.