some conpanies use famous people to advertise their products, coz many people aspire to be famous or at least respect famous's opinions. its also a well-know fact that most famous people are also very wealthy. so, if people see that someone famous is using a certain product, they get the impression that it is a quality product. another reason is that famous people are usually attractive. having an attractive person in your advertisement draws in people's attention. and will keep people's attention than unattractive person.
Celebrities are hired to promote products because there are people who are obsessed with their lives that the consumers (customers, potential buyers) will buy whatever they promote.
bandwagon
I would advertise a free trial and the price and that it is frisk free trial or money back. Also advertise how long the free trial would be and what my company promotes to people. A product that is well used and popular with customers and a better price.
Endorsement
To advertise so if your product is liked, then whoever used it may spread the word and buy more of your products.
Companies make athletes advertise them and their products because they believe that if people see that a popular athlete (whom they like), likes a certain company or object fans of this person will buy from the company or the product. In return the athlete gets a sum of money. Also athletes are not forced to advertise a company or product. They advertise the company if they WANT to.
Classified Listing are the listing of any products, where you can advertise your product like you can advertise your website of used car for sale or sale of number plates.
Coca-Cola
There is a product called Rogain that is reputed to regrow hair after it has been lost. There are also clinics that advertise the restoration or regrowth of hair.
IncomeAtHome, a dot-com work-from-home product, has been and still is a sponsor of The Glenn Beck Program.
Spam is used to advertise a company or product, so often spam will replicate itself and avoid being deleted until the consumer agrees to use the product.
The Naked and Famous - Young Blood?