Are advertisements aimed at teenagers ethical?

This can be seen as a question that requires an opinion rather than an absolute answer. So, the authors of these commercials might find them ethical.

Personally, I find them unethical. Teenagers haven't yet experienced the real value of money (haven't worked or not a lot) so they can't yet make an informed choice about the product: whether it's worth the time they spent making the money that it costs. This means that the advertisements are influencing the teenagers not to decide whether they need the product, but to demand of their care givers to buy it for them.