B&H Photo Video offers the TP-Link Smart WiFi Light Switch 2-Pack for $79.99. Clip the on-page 50% off coupon to cut that price to $39.99. With free shipping, that's $5 under our May mention and the lowest price we've seen. (It's also $10 under the lowest price we could find for this quantity elsewhere.) It's compatible with Android and iOS devices via the free Kasa app and works with Amazon Alexa for voice control of fixtures and any WiFi router.