how can I randomize my MAC address every time my WiFi is turned on? Given the increased prevalence of systems which track people's movements by their Mac addresses I'd like to obscure mine.

I have a rooted galaxy note 2 with busybox installed.  I can change my MAC address like so:

busybox ifconfig wlan0 hw ether 11:22:33:44:55:66


however, if I disable and re-enable my wireless, or I reboot my phone, it gets forgotten.  is there somewhere I can put a script so it will be run every time my wireless turns on?
How about Chainfire's tool Pry-Fi which was announced over at XDA?
It works great and it is available via the official Google play-store at:


https://play.google.com/store/apps/details?id=eu.chainfire.pryfi


Here’s a screenshot showing the tool in action…