Application for Android lets you share the Internet with other devices in return for virtual money baptized OG.
You can use the "OG coins" (Ethereum tokens) to access other users' Wi-Fi or even swap to real money.
Open Garden (apk here) requires Bluetooth, Wi-Fi and location to be activated. For sharing to be done, note that the host device must be connected to the power source.
Compare with AnyFi, Net Share, Manet (requires root), and SmartMesh.
And see also: Apps allow you to send messages without Internet