Sarah tells jake that she is thinking about buying a car. jake replies that he would like to sell sarah one of his cars in a few weeks for a really good price. jake has made:

I would say that Jake has made a word-of-mouth offer based on knowing Sarah so this does not depend on advertising but on direct knowledge of the interested buyer and this can be a very effective way to sell things and also with seeking contracts for consultants in the form of networking it can also be very effective.