Or does the music have to be royalty free? Just like to know because I’m going to AP2016.
I doubt it, as long as you paid for the song on iTunes or whatever.
Yeah, you’re good.
If you are concerned though, all of Bach is public domain
Any well-run yoyo contest has paid for and secured a license from BMI/ASCAP/etc for use of licensed music in a public performance space. So you can use whatever you want, it’s been paid for.
Beyond that, if you want them to be able to upload your freestyle, keep in mind that some songs are rights managed on YouTube in different ways. Some are allowed by the rights manager, but YouTube will insert ads into the video to monetize it. Some are not rights managed at all. Some are blocked only in certain countries, and others are 100% blocked and will get that YouTube channel a Copyright Strike (three of those and they delete your channel and all of your content).
So, from a contest perspective, use whatever you want. If you want to make sure video of your performance is available everywhere, I’d recommend trying to find some royalty-free music that suits your needs. Here are a few sites that I use: