Two-Part Pricing: Two-part pricing involves charging customers an access fee or cover charge to gain the right to purchase the good itself.  Simple cases where firms can identify consumers and prevent resale allow two-part pricing to replicate the perfect price discrimination solution and can be thought of as a mechanism for implementing this outcome.  In the case where consumers are different and difficult to identify, some surplus is lost since the firm must price both the entry fee and the good in a way that discourages imitation of one consumer type by the other.  The example discussed in this section (pp. 337-338) is complicated and worth a full treatment in lecture.