Cafago offers the Sonoff RF to Wifi Smart Home Switch for $15.39 $15.52. Coupon code "JS1728" cuts it to $11.39 $11.49. With free shipping, that's the lowest price we could find by $2. It's compatible with Google Home and Alexa devices and makes 433MHz RF devices remote controllable via the eWeLink app for iOS or Android.

Note: This item ships from China and may take up to four weeks to arrive.