These comm kits you speak about are the ones marketed as "referee communications systems" - a fancy name for radios (transmitters and receivers). You can get good radio systems (essentially Walkie talkies) for much less than these "professional" sets. A communications system is made up of a few basic components... Receiver: A transducer to pick up the baseband (microphone picking up your voice), a synthesiser (to create a high frequency carrier wave (to carry the base and signal), an Audio Frequency amplifier and a Power amplifier (to get the distance).... then it needs an antenna. A transmitter is pretty much the same except you use an oscillator to remove the carrier wave, so you are left with a baseband signal for an earpiece. Sounds complicated but it's really not. You can pick up a good PTT radio system for a few hundred quid. They are just compact walkie talkies. Because big company's put there brand on it, that makes them more expensive. A plain fruit of the loom t shirt with no logo could cost you £5. The same t shirt with a Nike tick would cost £30.
I completely get what your saying and again I reiterate I'm simply researching a product