Royalty free music, such as the music on this site, is basically music with a specific license that means the licensee does NOT have to continue paying fees after getting the initial license. This does not mean that the initial license is always free, however.
Creative Commons is an organisation that provides a copyright licensing framework for those that wish to share their creations freely with the world. The music on this site is all Creative Commons Attribution 4.0. This means the music is free to use as long as you give credit. Learn more about Creative Commons here.
Despite the fact people use this term all over the place, "copyright free music" doesn't actually exist! Today's intended meaning would be something more like "copyright claim free music". All music has some sort of copyright. It's not just some crazy free for all. In any case, I can assure you that you can use this music without fear of falling afoul of copyright laws.
Under the Creative Commons Attribution 4.0 terms, you can use this music for ANYTHING - just so long as you give clear credit for anyone that wants to know who made this music. Check out the FAQs for more info.
Absolutely not. This is 100% free to use as long as you adhere to the Creative Commons license as stated above. However, I will love you forever if you would consider supporting me with a donation or patronage. This free resource depends on the generous donations of music enthusiasts, just like you! Learn more about how you can help me out right here. If you are unwilling, or unable to give credit, you can also purchase a one-time license to cover you.
I have no idea, you should probably scroll up to where all the music is.