Most people who build robots make them autonomous, but I did just add a basic transmitter/receiver circuit for the initial testing stages of my robot. I am just using one data line so I can turn the robot off in case it wants to run away. This tx/rx pair allows for 16 commands (4 data lines, 4^2). Anyway, all I used is the TWS-434 transmitter, RWS-434 receiver, the HT12E and HT12D encoder and decoder. I also found, for my application, I needed a digital relay to switch the voltage. I'm sure it could be done many different ways, but this was what I found and it doesn't cost much.
