Cloud computing services are being provided in pay per use fashion. The cloud consumers are given two ways in which they can obtain computing resources. They are on-demand and reservation plans. The reservation plan is relatively cheaper than that of on-demand. In case of reservation plan the cloud consumer has to pay money in advance. However, making reservations for computing resources in well advance has some problems to consumers and also service providers due to the optimization problem. Optimization of resource provisioning cost is essential to make is suitable for both cloud service provides and cloud service consumers.