This blog post explains in the detail the concept of ePins and how they are used in our plugins (Binary MLM Pro and Unilevel MLM Pro).
ePins are somewhat similar to prepaid mobile recharge cards. You go to a super market and ask for a $10 recharge card for your cellphone. You scratch the card and it shows a 16 digit number and a way in which you can input that number in your cellphone. Once done, the balance on your phone gets an addition of $10.
ePins operate in a similar fashion. As a site owner you would generate ePins in the WP Admin interface of our plugins (you can define the desired length of the ePin from 8 to 15 digits). You would also create Products / Plans using the WP Admin interface of your plugins. Each ePin would be associated to a particular product / plan and would hence have a monetary value. As a site owner you would provide these ePins to either your existing members, who would use them to register new members in their downline, or you would provide them directly to prospective customers at a seminar / workshop. You would collect the money for the ePin from either the prospective customer or the existing customer. These members would then register on your site using the allocated ePin. Since the ePins have already been paid for the registering members are automatically marked as paid in the network. The commissions as defined in the plugin settings would also be distributed for these newly registered members.