Hi Kai,
Many thanks for your message and the kind words about trakAxPC.
All the loops, beats and full tracks available on trakax.com are royalty-free, so there is no problem with using them as a YouTube soundtrack. You may also use all our loops and full tracks in commercial (for profit) projects.
Royalty-free means you may use the music in anyway you would like (soundtracks, video presentations, tv/radio/web advertisements, podcasts, videocasts, websites etc.) without any further payments or license fees - once you make the purchase, you can use them whenever and wherever you choose. Our pricing structure (starting at $1.99 for bundles of 10 loops and $12.99 for full tracks) is some of the best value on the web and we use some of the best producers out there including Loopmasters, Zero-G and Wavtracks.
The only restrictions is that you may not resell the loops or full tracks in their original format (ie. they must be part of a music composition or film/video project and you cannot resell them as loop packs).
You can learn more about this from the trakPacks FAQ section.
If you require any further info or have any questions at all, please drop us a line at any stage.
Thanks again!