These Z-Wave Plus Smart Wall Sockets with 2 USB ports drop from $29.99 to $19.99 at Monoprice. Add two to your cart and apply the code ZWV and you'll drop your total from $39.99 to $34.98. Plus the shipping is free. The lowest price we found for a single one of these outlets anywhere else was $29.90. These smart plugs are compatible with a number of smart hubs, like the Samsung SmartThings Hub and Wink Home Hub. Once connected to a hub, they can be controlled using a smartphone, Google Home, or Amazon's Alexa. Sales tax is charged in most states.