Help? What should i do?

I love the fact that i can just go on youtube and listen to music. But its not like i can take my computer with me when i go on walks. I wanna listen to music when i walk, and i take long walks too, so that's even more frustrating.. I'm only 15 so i can't pay for iTunes and my parents don't want to anyways because they have money issues to begin with. I have an Mp3 but it has old songs and theres only about 70 songs on there. Not only that, but i probably know all the lyrics to everyone one of those songs because ive listened to it so many times and its annoying. I wish i could listen to my favorite bands, modern music. Any ideas of how i can do that? And if you suggest limewire or any other site like that, i cant risk getting a virus. =\ thanks a ton.