OK estimated 60-80. The author designed a board, called CANard, to help sniff and program on CAN bus on cars. This would have been handy for me a few months back as I was struggling with figuring out how to program Tire Pressure Sensors on my car. And instead of paying a dealer, could have maybe reverse engineered it and done it myself. The board hasn’t been pulished yet, but I will keep my eye out for it.
http://www.forbes.com/sites/thomasbrewster/2015/03/25/hack-a-car-for-60-dollars/
UPDATE:
found the opensource project
https://github.com/CANtact/cantact-hw