I'm always skeptical of folks who claim that they know the one source of all your problems, and conveniently the solution, which often involves you buying something. Well, I won't claim to solve all your problems, and you definitely don't need to buy anything. I can promise you that if you follow my advice, you will feel better, save money, and play a small role in undermining the modern industrial capitalist system.
There are five simple things that anyone can do. By doing them you will immediately have improved self-esteem, you will find you have most everything you need, and you will have a more peaceful life.
1. Look around your house until you find your tv. Now look some more to see if there are others. Especially look for televisions in rooms frequented by children and teenagers. Disconnect all the wires and remove the televisions from your home. Advertise them on freecycle or kijiji or find someone you don't much care for to gift them to. Now call the cable or satellite company and cancel your service. That will feel good, and will save you somewhere in the order of a thousand bucks a year (you're welcome) but the biggest benefit is that now you will not be exposed to television advertising. You will also not be tempted to watch Jersey Shore or Bounty Hunter or any other programming that makes you feel dirty for having watched it. You will be able to watch whatever you want on your computer (I know you have internet) and if you can't figure out how, hire a teenager for a couple of hours. We've been tv-free for more than 3 years, and cable-free for 3 years before that, and I can say with certainty I haven't missed it.
2. Go bravely into the interwebs and find yourself some ad blocking software that works with your browser. I've used both Adblock Plus for Firefox and Adblock for Safari. These are both extensions to your browser that block all banner ads and most other ads, even on facebook. This will change your web surfing experience dramatically. You will wonder how you ever managed to read a newspaper online before, and you will feel very smug indeed. You may wrestle with your conscience about whether you are stealing content by not watching advertising, but I will leave you to do that in private.
3. Spend a little time with the presets on your radios. Make sure they all point to public or advertising-free radio which in Canada means Radio 1 and Radio 2 (and maybe campus radio?). Don't let radio advertising get in your car or into your kitchen while you are cooking supper because nobody needs that noise. Also, you will find yourself exposed to all kinds of current affairs and music that you wouldn't hear on commercial radio. This you can do with a perfectly clear conscience, as you have already paid for these services.
4. Whatever you do, don't go to a mall. Just don't do it. Everything there is designed to exploit your insecurities so that you spend money on stuff you don't need. If you don't go there, you will never even realize how hopelessly outdated your wardrobe is, or that you don't have the latest version of whatever iGadget you have in your pocket.
5. Lastly, and for teen girls most importantly, do not read fashion or other women's magazines. They are designed for one thing only, which is to convince you that you are a vile and unworthy human because you actually have flesh on your bones, and to feel better, you should buy stuff.
By doing these things, you are kicking advertisers and their corporate overlords out of your life and you will be better for it. You will not find yourself humming stupid jingles or wondering if you should try some miraculous wrinkle cream, or new car, or no-medical life insurance. Instead, you can fill that empty space in your head with whatever you want. And that, in the 21st century, is revolutionary.