The 1km requirement is the killer for this plan, as you run into radio regulatory requirements. There is the "Weightless" system operating in the old analog TV bands, but I'm not sure that's made it into shipping products yet.
https://en.wikipedia.org/wiki/Weightless_%28wireless_communi...
These aren't crazy cheap but meet all your other requirements:
http://flutterwireless.com/
LoRa is a low power,low data rate modulation scheme that can transmit miles. Modules are starting to be available: http://www.microchip.com/design-centers/wireless-connectivit...
The really missing piece is the connectivity, I need something that can read data somehow and then transmit a point A to a point B, where A and B are at least 1km away from each other...