There are still many issues to achieve collaborative Wi-Fi sharing: the legal liability of the sharer; high data access costs in some situations (mobility when going over a monthly subscription quota, roaming…); no appropriate incentives to share. Current trust management could exclude the malicious users, but still could not foster Wi-Fi sharing. We have extended an appropriate trust metric with cooperation incentives to mitigate all the above issues. We have evaluated our proposal with a trust metric and incentive effectiveness through simulations and we have found the bootstrapping time for such a system and the average depletion time for its users linking it with the size of the system's user base, proving the feasibility for such a combination.