Yeah, it isn’t just the cost of the microphone, interruptor switch, transmitter, and receiver, which - other than Telex - are really quite affordable. The field mic system has to connect to the PA system, and many existing PA systems may not be able to accommodate the microphone system. If not, then the school would need to procure a whole new PA system, and not many are willing to do that just to have referee announcements.
But, a field mic is immensely valuable, to explain happenings on the field, re-set the game clock, etc. I wish every stadium had one.
Don’t try to remove the field mic before you get off the field. Get to your dressing room, and remove it there, whether the operations guy likes it or not.
Avoid the over-ear mounted microphones. I bought my own lapel microphone and interruptor switch, to avoid using the over-ear mics. About $75. Unfortunately, the pin connections on mics vary with manufacturers, so it only works with Shure systems. Might work with Telex (Electro Voice) systems, too - just haven’t had the opportunity to try it with a Telex system, yet.
The other issue is having an interruptor switch (also called a mute switch). Too many schools give us a belt mounted body pack transmitter, intended for use by a lecturer or speaker, with just a tiny mute switch on the body pack. Not good. You simply must have a separate belt-mounted interruptor switch. Telex are the best, with a true toggle switch. But, as I have, the other type is a Shure push-button type switch. Not quite as tactile as the toggle switch, but works just fine.
Yes, it takes a bit of practice to effectively make announcements. Don’t be afraid of it. Listen to NFL and NCAA guys on TV for how they make their announcements. Emulate the guys that are smooth, and don’t stumble with words.
You can do it.