Resources required

The £1500 for the advert costs includes the production of the advert, along with the broadcasting of it.
The cost for 4 shows a month on a Community Radio Station would cost £30
For a local radio station it would cost £200.
The start up costs are so expensive because the equipment is expensive, the products are all new. But in time the adverts will pay for this, the only thing that will need renewing is the PRS license.

*The devices I expect a radio station to already own are:
Chairs
Headphones
Microphones
PRS License
Computers and monitors.