Complex sentence: A major drawback is that P25 is not manufactured for amateur use and commercial grade equipment must be used, and the cost of commercial radios that employ the P25 technology were even more expensive than that of off-the-shelf D-STAR radios.
Split into simpler sentences: A major drawback is that P25 is not manufactured for amateur use, so commercial grade equipment must be used. The costs of commercial radios that employ the P25 technology were even higher than that of off-the-shelf D-STAR radios.