Grid economy provides a mechanism or incentive for resource owners to be part of the Grid, and encourages users to utilize resources optimally and effectively. Advance reservation technique allows users to request resources in the future. However, few research has been done on determining pricing of such reservations. In this paper, we present a novel approach of using Revenue Management (RM) to determine pricing of reservations in Grids in order to increase profits. Hence, the aim of RM is to periodically update the prices in response to market demands, by charging different fares to different customers for a same resource. We evaluate the effectiveness of RM and show that by segmenting customers, charging them with different pricing schemes and protecting resources for them who are willing to pay more, will result in an increase of total revenue for that resource. Moreover, using RM techniques ensure that resources are allocated to applications that are highly valued by the users.