1. go with free material right from the beginning. search for myspace artists, there are bands for every genre and they will give you their souls when you spread their music.
2. live with the fact that your a dumb guy and tell people to live with the fact that your vid has no sound
3. (and here is where the magic starts) use any video editing program that you used to make your movie and change the audio track. you only have to change the pitch by a few cents, percent or degrees, whatever it is called in your program. this works because youtube lets a robot run over all new entries and if it recognizes a certain data structure, the audio is deleted. but with changing the pitch, you pretty much create a new mix that is not detected. you might say now, "huh, cool, but my nigga beat is fucked up when i change the pitch". if you think like this, then first off you should try to use different music than hiphop cuz its getting old imo. second, if you just change the pitch by close to nothing you hear like no difference.