I just picked up a couple of pairs of Ecobee 3 sensors at Walmart for $40/pair. If you check the Walmart App, the online price still shows $79, but if you change the seller to Walmart and then check the stores, the list will show stores that still have stock and show the price of $40.
I’m in the Rockford - Chicago, IL area if that makes a difference.
Some of the other HA stuff was also on sale or clearance.