There are cellular network providers that specialise in IoT applications, where you pay monthly per device and data transferred. This is the first one from a se

There are cellular network providers that specialise in IoT applications, where you pay monthly per device and data transferred. This is the first one from a search for "IoT Cellular": http://www.aeris.com/technology/aerconnect/ http://www.aeris.com/technology/aerconnect/ Particle run their own, but by the looks of it you have to use their Electron hardware: https://www.particle.io/cellular https://www.particle.io/cellular If you could get people to install an app on their phone, you could use Bluetooth LE to passively collect the data as they walk past. There's a few asset tracking solutions that use this approach, such as Tile: http://www.wired.com/2013/08/tile-a-better-way-to-find-your-lost-keys-and-maybe-your-stolen-bike-too/ http://www.wired.com/2013/08/tile-a-better-way-to-find-your-...