The current LTE-Advanced (LTE-A) standard has been designed for human-generated traffic but it has to be adapted for machine-to-machine (M2M) communications due to the expanding Internet of Things (IoT) market. Although most M2M devices infrequently connect to the network and transmit small messages, a serious congestion may occur during the initial channel access phase if a massive number of devices activate near-simultaneously. To address this issue, previous studies have proposed load control methods based on broadcasting an access probability to all nodes or groups of nodes at times of congestion. Such approaches, however, are inadequate in satisfying the wide range of service requirements of IoT applications. Here we propose a pricing-based load control and service differentiation method for M2M traffic over LTE-A which is based on charging M2M devices for each successful channel access and subsequent short message transmission. By increasing the price during congestion, the proposed method effectively controls the access load. It also operates as a service differentiation mechanism providing delay-sensitive nodes a shorter access delay and charging higher prices from them. Simulation results show that the delay performance of the proposed method is close to an optimum load controller; and, it provides service differentiation unlike previous load-control approaches.