You must not forget that there are always minimal costs, regardless of where the station is located. There is no way around it; you have to pay for your electricity, your transmitter, telephone service, etc.
There are, of course, large radio stations. For example, some stations have penetrated the market, such as Radio Beauséjour, which has 18 full-time employees. However, some stations don't even have one half of a full-time position.
I would estimate that it costs at least $100,000 per year, but once again, it is all relative. Your question is very vague, because you have a small station with a small radio, a small transmitter, low operating costs and a small facility.