Where can I find Billabong/Jansport backpacks?

[I love you:)]

I just started high school a week ago, and I bought a bag. But it was soooo heavy and my shoulders were like in so much pain! And everybody else had backpacks so now I'm like, ok I need one! Some popular brands are Billabong and Jansport. Does anybody know what stores I can get them in, even though its kind of late into the season?

Thanks!