[BirdOPrey5]

On the left side menu of the Admin CP, below "User Titles" and above "Avatars" is "Paid Subscriptions" - In there you'd "Add New Subscription" to put in the details/text of the subscription, you can have several options like that site. (Platinum, Gold, Yellow Ribbon...) Of course it's not that simple, you also need to setup a payment gateway such as PayPal, but there are others as well- you'll need to sign up for an account with 1 or more of them and put your settings into the appropriate places. You should also setup new usergroups to put paid members into, usually with more benefits then non-paying users.