We consider a cellular network where intelligent cellular devices owned by selfish users are incentivized to cooperate with each other by using tokens, which they exchange electronically to 'buy' and 'sell' downlink relay services, thereby increasing the network's capacity. We endow each device with the ability to learn its optimal cooperation strategy online in order to maximize its long-term utility in the dynamic network environment. We investigate the impact of the token exchange system on the overall downlink network performance and the performance of individual devices in various deployment scenarios involving mixtures of high and low mobility users. Our results suggest that devices have the greatest incentive to cooperate when the network contains many highly mobile users (e.g., users in motor vehicles). Moreover, within the token system, devices can effectively learn to cooperate online, and achieve over 20% higher throughput on average than with direct transmission alone, all while selfishly maximizing their own utility.