I really don't like to pay for 3g access for smartphone, but i like to access my things afk. We already pay for internet connection on our houses and offices, imagine if we expand our wifi network all over the city?
Pretty sure that everyone already think about it, so this idea it's not innovative.. but doing something good is a step to change the world too.
The idea is to use an Onion Omega 2 board to act as a router and monitor bandwidth usage from connected users, then updates a webserver ratio system. If you provide bandwidth, you have more bandwidth to spend on another wifi connections from freenet. That is the basic idea.
Another feature is the device be a Tor Relay too, this can potentially spread Tor network and helps to improve the freedom over communication.
I know, "it's no so simple" or in a good brazilian portuguese: "Sabe de nada inocente!" , but i will give a shot to design a system to perform this task, if someone want to