This paper considers the problem of scheduling a set of independent tasks with multiple QoS requirements, which may include timeliness, reliability, security, version, and priority, in a Grid computing system in which resource prices can vary with time during scheduling time intervals. This problem is referred to as the QoS-based scheduling problem with time-varying resource prices. In order to solve this problem, a static scheduling algorithm (QSMTS_VP) is developed. The simulation studies carried out show that QSMTS_VP is capable of meeting diverse QoS requirements of many users simultaneously and that QSMTS_VP can react to the dynamics of the market. Thus, QSMTS_VP is a promising heuristic that can be deployed in a computational market.