Advertising is apart of the promotional mix. In fact, it¡¦s the largest and most important element of the mix. It is the most expensive and most complex part as well. An ad about a company informs the customer on what the product or service is. The main purpose of advertising is to educate and sell. When the customer buys the product or service you are advertising, the company has succeeded. Advertising is essential to a company and without it, everything would be lost.