Advertisements (Or "Advertising) influences people to buy products they may not need or are beyond their ability to afford. Most of the time, many customers become disappointed when they find out something in *(or about) their products which they were not informed about before. *"in" works if you are talking about something like food or a product like face cream. Use "about" as in "something about their products" if you mean something like the clothes you buy are from a sweat shop or something like that.