Tell us what you are trying to do and we might be able to help. Here in the US someone will use a simple FM broadcast transmitter to play music that can be heard on their radio at home or in a college dormitory. They are low cost - and permitted if the power and antenna is limited. There are transmitter and reciever modules that are used to send and recieve data - generally they are UHF (450 mHz or so) and short range as well. In the US some VLF (150 kHz) or so experimental operation is permitted too and people use that band.