Today's mobile terminals have several access network interfaces. In practice, the use of different access technologies is subject to different interconnection costs, and mobile users have preferences on interfaces jointly depending on performance and cost factors. There is therefore an interest in defining “light” yet rational multipath communication policies less expensive than greedy ones such as with basic Multipath TCP (MP-TCP). We analyze the performance-cost trade-off of multi-homed end-to-end communications from a strategic standpoint. We model the communication between multi-homed terminals as a multi-criteria non-cooperative game so as to achieve performance-cost decision frontiers. The resulting potential game always allows to select multiple equilibria, which correspond to a strategic load-balancing distribution over the available interfaces, possibly constraining their use with respect to basic MP-TCP. We specify how the resulting model may be in practice implemented by users willing to jointly control the interconnection cost and the performance, based on user Quality of Experience (QoE) assessments. By simulation of a realistic 3-interface scenario, we show how the achievable performance is bound by the interconnection cost; we show that we can halve the interconnection cost with respect to basic (greedy) MP-TCP under a reasonable trade-off, while offering double throughputs with respect to single-path TCP.