Is there a fee or license to use PTToC radios?
Are you referring specifically to Motorola?
For Motorola WAVE, yes.
For the other brands, yes. (ESChat, BeON, all the Chinese PTToC CCR's)
Servers are involved to route calls, authentication, etc.
Plus, there's the cost of the cellular service. Some roll that into the cost of the service, some require the user paying for that.
The end user does not need an FCC license, since that's handled by the cellular carrier.