IoT monitoring systems tend to generate and transmit a staggering amount of data to the cloud for further processing over the course of time. While some of these data must be sent to their applications in the cloud in a timely fashion, not all data are needed to be available in a real-time manner. For such delay-tolerant data, we propose a scheme to improve data transfer cost, especially on wireless IoT-gateways which use the cellular network, by delaying data transmission to the eleventh hour. The delayed transmission will enable us to compress more data together and select a more suitable wireless IoT-gateway. The wireless IoT-gateway selection mechanism is made possible by our proposed mesh wireless IoT-gateway architecture. The advantage of meshing wireless IoT-gateways together is that it provides stable internet connections via fault tolerance and bandwidth aggregation. In this paper we propose an IoT-gateway selection scheme to meet the maximum data deadline with minimal data transmission cost. Our simulation results comparing our scheme with the Deadline-Cost scheme show that while both schemes lead to less than 1.5% data deadline missed, our proposed scheme reduces the cost by 75%, and its strength is more apparent in a congested network.