Fashion has existed as long as human beings have. We can't separate fashion from our lives, nor could our grandparents and their grandparents (and the list goes on), because fashion always had a purpose in our lives.
But the purpose is different for each of us. It could be simply because we need clothing to walk around in the freezing winters and scorching summers. Or because of how we see ourselves in the world, want to express ourselves, and fit in with that group that we admire. Or maybe you have other reasons.
But whatever the purpose is for you, be honest with yourself about it. Why do you want that next fashion piece? Is it because of yourself? Does it make your life better? Does it help you be what you want to be? Or, do you want it because that person on TV had it?
I'd think twice before clicking on that "Buy Now" button.