CC2511 - 2.4 GHz Radio Transceiver, 8051 MCU, 16KB or 32KB Flash memory and full-speed USB interface
Texas Instruments
Texas Instruments - CC2511F8
$2.71 - * $8.27
Texas Instruments - CC2511F8 SP
Texas Instruments - CC2511F8RSP
$4.10 - * $8.27