Parking lots in most major cities service at least two very distinct types of (market) segments: the first one, comprised of non-subscribed (drive-in) customers that pay variable (higher) fees according to their time in the lot; and the second one, comprised of subscribed customers who pay a fixed (flat) discounted rate. Thus, parking lot operators face the decision of how many subscriptions to sell in order to maximize their revenue, taking into account that denial of service (lack of available parking spots) produces negative effects on their long-term success. In this paper, we develop an approximate solution for this problem based on integer programming and discrete-event simulation techniques and apply our approach to a case study in the city of Bogotá.