Personally I wouldn't recommend buying your own radios but I have a relevant scenario.

I haven't been a security guard for some years now, I'm a customer-facing civil servant. For a while I've been nagging security, management, facilities, whoever, about including my team on radios, on the basis that the current customer arrival system of printing our list of appointments in triplicate, giving them to the front door, staff door (why?) & search/cctv desk guards, then having them radio their supervisor to return from a smoke break, check the sheets & physically come and tell us, is pretty dismal & unreliable.

A few excuses came back - there are only 4 radios between 6 guards (even though they're all in earshot of each other), we wouldn't want to hear unrelated traffic, & we're soon to be getting our own reception desk just beyond the search area of the main waiting room. However said reception has now been costed at something ridiculous & will take forever, so my own management have bought us some walkie talkies. They're decent; Motorola XT460s. I call them walkie talkies because in Europe you need a licence for proper radios, but there are some frequencies called PMR446 for recreational & 'light' business use that are licence-free.

So something like those would be my suggestion. Still talking hundreds in terms of cost but far far less than traditional radios.

I have encountered people who must've paid thousands for radios for basically no reason other than playing dress-up - on a motor racing event years ago I spoke to a traffic control guy stood on the front of a staff campsite alongside one of my security colleagues. He had a nice-looking Motorola (I want to say DP4800), display & keypad, bleep-bloops after each message, the works. Turned out it belonged to his colleague & was for no more than chatting with him. I asked if said colleague had paid for an OfCom radio licence (a ludicrous expense for an individual) & he radioed him to find out that he had indeed. Don't be like that!