Advance reservation allows users to request available nodes in the future, whereas economy provides an incentive for resource owners to be part of the Grid, and encourages users to utilize resources optimally and effectively. In this paper, we use overbooking models from Revenue Management to manage cancellations and no-shows of reservations in a Grid system. Without overbooking, the resource owners are faced with a prospect of loss of income and lower system utilization. Thus, the models aim to find an ideal limit that exceeds the maximum capacity, without incurring greater compensation cost. Moreover, we introduce several novel strategies for selecting which bookings to deny, based on compensation cost and user class level, namely Lottery, Denied Cost First (DCF), and Lower Class DCF. The result shows that by overbooking reservations, a resource gains an extra 6-9% in the total net revenue.