About royalty free music...if you are doing this just to learn, then yeah, go for it. If you are doing it for a youtube video, it doesn't matter. But if you're doing it for a festival, rest assured that the selection committee has heard those same exact tracks you've used a thousand times before. Is it a mark against you? I can't say for sure (sometimes it seems like the music is barely a blip on the radar in the no-budget scene) but you definitely aren't going to stand out from the crowd, for good or for bad.
Another thing to bear in mind...as you are learning and practicing, there are lots of composers out there in the same place. They want to learn and practice too. If you feel you aren't good enough to pay someone to compose music, find someone who is on the same level as you. Help him or her learn as you are learning, rather than just throwing down generic music. We're all in this together.