What are royalty free music? Are they some special type of music or something? I always see people talking about royalty music, but I don't know what it means. Please explain.
Music where you dont have to pay royalties. Once you buy it, you can use it again and again without having to pay each time. But be careful because different sites put different terms and conditions when they sell you 'royalty free' music. For example, it is quite common to find that you can buy a song and use it as many times as u like for your video as long as that video is not being used in a commercial manner. If it is, then you may have to renegotiate etc etc.
Technically you are not actually "buying the music," as such, you are buying a "license to use the music." So, in a sense you may own a copy of the music ( much like buying a CD), and you agree to a license which has specific clauses of what you can use the music for. Once a royalty free licensed is purchased, you do not have to pay any further costs. However, broadcast royalties ( collected from TV, radio stations etc) can still be gotten by the copyright holder ( or composer) from the broadcaster if a cue sheet is filled out. Have a look at this license agreement page
http://rocksuresoundz.com/licensing/ for an idea of what a license is like, and check out the FAQ page as well if you still need to understand it more.