Here's an idea to those who are to young to have a credit card...give your parents, uncle, whoever the $10 and let them pay for you. Unless you really have no money or for some odd reason find no use for the competition, I can't see why you shouldn't enter.
Remember, the bigger this competition gets, the more people will sponsor it. This means, that the competition could end up giving the winner a gift voucher for e.g. 1000 manufactured singles of the winning track with perhaps an established artist, hardware, software, interviews in a Hip-Hop magazine (either online or published) etc...but the only way this can happen is if people join and support the competition from day 1.