If you decide to broadcast with Live365.com, they cover your royalties if you buy a Personal Broadcasting package. Professional packages requires a royalty fee paid to Live365.com and then the company handles payments on your behalf.
If you endeavor to be a profit-making webcaster, depending on your status, you might qualify to pay royalties based on a percentage of your revenue. Larger commercial broadcasts fall under other guidelines.
That said, different classes of online broadcasters (non-profit, etc.) have different rates.
For a complete explanation of the current royalty situation that applies to webcasters, see the Summary of the Determination of the Librarian of Congress on Rates and Terms for Webcasting
The Bottom Line
Your expenses are going to vary greatly depending on how big of a broadcast you plan to create. Aside from fees paid to a third party to host your broadcast, you may decide to invest in a computer to act as a server which can cost up to several thousand dollars.
Other potential expenses you might incur include the cost of electricity, the cost of CDs or music files, a microphone, a mixer board, DJ talent fees and even promotional expenditures should you decide to create a live, revenue-generating online radio station.
Whichever direction you should decide to go in, remember: your first priority is to please your listeners and always try and keep it fun!