I just checked on digikey Beaglebone Black revision C is way less than 100$ and there is thousands in stock. I've used Beaglebone's in industry grade projects.

I just checked on digikey Beaglebone Black revision C is way less than 100$ and there is thousands in stock. I've used Beaglebone's in industry grade projects. To my knowledge they are still in use after several years of operation with no hickups.