Yes, sure! You can buy a Sonoff RF and you are good to go, I guess. But I didn’t and I was not so sure about the no-named RF receiver so I ended thinking about adding my own.
But first things first. The Sonoff is an ESP8266 based smart switch by ITEAD which comes with custom firmware that communicates with the manufacturer cloud to provide “smart” capabilities like remote switching or scheduling. The cool thing is that it has a line of pins that expose the VCC, GND, RX and TX pins of the ESP8266 and a buttons attached to GPIO0 so very soon it got hacked and there are a number of firmware projects already available. I’m not an early adopter and some work has been done and reported by Peter Scargill, Javier or even in instructables.