Nest’s iconic thermostats don’t go on sale often, and sizable discounts on their other products are even rarer still, so Black Friday really is the best time of year to join the ecosystem, or expand your collection. Save $50 on the third generation Nest Learning Thermostat, $20 on the Protetct smoke detector (both the battery and wired versions), $50 on the outdoor Nest Cam, or $60 on the indoor one.