Style??? HELP!!!!!!!?

I'm 14 years old. Kinda boring, just wear champion short shorts or quick drops and a tshirt. I really like mix matchy type style like Selena Gomez on Wizards of Waverly Place... I like how she totally doesnt match but it still comes together somehow... Can you please find me a website where I can find clothes and accessories like Alex? and cheap please! I really dont care about name brands or anything either.