http://www.amazon.com/DROK-Wireless-Receiver-Infrared-Controll/dp/B00LY0BT4Q/ref=sr_1_12?ie=UTF8&qid=1449087876&sr=8-12&keywords=ir+remote+control+board

there's cheaper RF remotes out there, but they don't come with a relay.

http://www.amazon.com/Generic-Channel-Wireless-Controller-Control/dp/B00EQ1V5BW/ref=sr_1_14?ie=UTF8&qid=1449088294&sr=8-14&keywords=rf+remote+control

Edit: You can build one from scratch, but it'll take longer, and probably cost you more (i'd looked into it a few months ago).