There's also Zigbee[1] which was specifically designed as a radio protocol for home automation, in which each device has a relatively short radio range but works on the assumption that if you're automating your home there's likely to be devices all over the place which can mesh together. I've not used it myself, but it looks to be pretty popular amongst manufacturers.
If it sounds too good to be true, it is - they had to break a perfectly good protocol by making it closed and requiring a costly license to use it. If we want good, consumer-friendly IoT, it needs to be built on a protocol that people are free to hack on in their garages.
For a less nifty, but probably also less complex solution, I'm using Ciseco radio units to build some home automation at the moment. They're available for < $20, and with the right aerial have a range measured in kilometres (although more usually a few hundred metres). I'm pretty sure there's also a repeater mode on the actual radio modules if you need extra range.
ZigBee modules are available for less than $20 in single units. Just how much cheaper do you expect them to be?
The license may be expensive, but the manufacturer is making the interfaces by the millions and that cost is amortized across the base.
[1] http://www.zigbee.org/