The Robot Radio kit contains all the parts needed to make a two-way radio. The terminal connects to a PC to display text and the robot's radio plugs into one input and one output port (or one combined input/output port). The radios are Digi Xbee Pro two-way radios with a range of up to 300 feet. The cost of the radio is $97.50 (half of it in just the pair of radios).
Instructions for making the robot radio
Sample code for the robot radio
Video of a radio terminal controlling a robot