I've had good luck with the nRF24L01 modules. You can get them for less than $4 each on ebay. Here is a url with some guidance: http://www.atmega128.org/#nRF24L01
. They have good range, low power usage, 100 software selectable channels and can be used as transmitters or receivers.
Not sure I'd quite call it "good range" - I've used 343 and 868MHz devices which are inherently better range (100's of meters line of sight) - 2.4GHz with a PCB aerial can't compete mW for mW with longer wavelengths and a 1/4wave or dipole aerial. (also 2.4G has to compete with WiFi and Microwave ovens). The high power version is +20dBm which is needed for longer ranges (especially at 2Mb/s