At some small clubs it may be of lesser value, unless everyone is on the same channel.

As for expensive, not really too bad. Especially when bought with the radio. Also, how much is your time worth? Do you want to sit around and wait for your frequency to open up or just dial in a new one and fly. Even if you only have one plane you could carry a couple of spare rx crystals and swap them and dial up the transmitter to go fly.
Expensive is a relative term. To a beginner on a tight budget maybe, to many others it is the same as an expensive lunch. I fall more in the first category BTW, budget wise