If the goal of advertising is to make you spend more money than you otherwise would by targeting psychological vulnerabilities, then it will be difficult to justify it in an absolute moral sense. Its moral worth will likely have to stem from a utilitarian perspective. Does the overall effect of the advertisement help boost society? At this point, it becomes more a question of sociology and economics than one of philosophy. For instance, you could argue that the prevalence of ads have adversely affected mental health and increased wasteful spending habits. You could also point out that some aspects of the world would not be as effective without advertising, such as good TV programming or the Internet (this is already changing however).