Amazon offers the Hot Wheels AI Intelligent Race System Starter Kit, model no. FBL83, for $38.41 with free shipping. That's $12 under our December mention and the lowest total price we've seen. (It's the best deal now by $5.) It includes two smart cars, two controllers, and 20 pieces of track.
Walmart offers the Hot Wheels Criss Cross Crash Trackset, model no. DTN42, for $37.03 with free shipping. That's tied with a pickup mention from a month ago and the lowest price we could find by $8. It features over 16 feet of track and includes one Hot Wheels vehicle.