You could also use the word 'endorsing'.

Do you often see celebrities in ads for businesses? My question is, how can someone represent goods for some brand? I am finding that the word “represent” is not suitable for the situation, because lots of celebrities don’t care about the goods wether they are good quality or not, they do it just for the money, these things are happening in my country. To reply to your statement. In my country Serbia and in England where I lived 17 years these things are unfotrunately happening too. It's a marketing ploy to sell products. I understand your concern and agree with you because basicaly it's a lie. ploy - a cunning plan or action designed to turn a situation to one's own advantage.

The way you have it works--to show up in ads. You could also say: "Do you often see celebrities promoting a business in ads?" It could also be called 'representing a brand/product/company.