Telecom grade MW P2P links start at 20K and upwards. They do also however work on licensed spectrums. The new un licenses 24 50 and 60 ghz links can be really cheap, but I don't know how well do they compare to the bigger telecom ones. RF equipment is pretty darn expensive to make, the telecom one have pretty impressive "RF dark magic" eco chambers milled out of aluminum blocks and many other cool features. The new commercial ones seem to be pretty simple and mostly solid state not much more complex looking than your typical wifi router. How do they fair with weather and interference how well do they coexist with each other, and how reliable are they in the long run is another question. Some of those MW drums can operate for decades I'm not sure about the 300$ or even the 3000$ ones.