not an easy subject - I think the harsh reality is (just like the old Band II FM pirate days in the UK, Netherlands and perhaps various other countries) most people
don't or
can't! -
at least not the station itself.
Even with normal radio stations smaller specialist ones are losing money- there was an article in the British Guardian newspaper about one with national reach where the owner has had to put in £3 million of his own money and is still making a financial loss)
Also with intense and ruthless competition, long ad breaks will make people tune out to another station, the businesses who advertise on radio are also skint or getting the ads will limit the time you have to make content or force you to censor it to be family / business friendly with no guarantee of a return for the sacrifice of freedom of expression.
With pirates playing specialist dance music what happened is that record labels waived their copyright entitlement for publicity, there would be occasional ads for dance music events which part funded the station, but in many cases the DJ's themselves ended up having to contribute towards the cost of the station! And of course in some cases the sales of drugs funded certain stations. I do not suggest this, its illegal and can cause all manner of unpleasantness down the line.
For the 21st century : might as well forget about trying to make a profit from creative media. If it happens its cool but best just trying to "break even" or accepting that at least its not
too expensive a hobby project compared to pirate broadcasting (or many other things) and won't usually get you in trouble! (though copyright and decency laws
will be enforced against online stations if they aren't already...)
After all, you don't
normally try to monetize your pet dog by trying to train it to pull shopping carts for old people, nor your pet cat by hiring it out to folk with mice and rats in their house. it probably wouldn't work and might even get you arrested under animal rights legislation in many countries! - but lots of people the world over keep pets and derive much enjoyment from them. incidentally I noticed one of the Dutch adverts on the Belgian station C-dance is for pet supplies
what might work is to link your station to a website or portal where you can sell advertising, but remember people who listen to online music already detest being aggressively marketed to and expect a substantial amount of content for free (though they will pay for live events and well produced/high quality content).