I designed a ultra low low cost evaluation board (ULC-Zigbee) based in Kinetis wireless MCUs, take a look at the attached PDF for the brief description. I was able to build three of them at ~$10USD each.
The ULC-Zigbee is covered under the GNU General Public License. The required files to build the board are attached, it measures 30 x 50mm.
My partner AngelC wrote a sample code. The software basically communicates wirelessly the ULC-Zigbee board with a USB-KW24D512. An FXOS8700 is externally connected through the prototype board connector and the magnetic and acceleration values are then wirelessly transmitted to the USB stick, then the values can be printed in a HyperTerminal.
The attached zip file contains the following files: