According to psychologists, a compulsive spender wants to spend a lot of money because:

People can be addicted to different things, e. g. , alcohol, drugs, certain foods, or even television. People who have such an addiction are compulsive, i. e. , they have a very powerful psychological need that they feel they must satisfy. According to psychologists, many people are compulsive spenders: they feel that they must spend money. This compulsion, like most others, is irrational — impossible to explain reasonably. For compulsive spenders who buy on credit, charge accounts are even more exciting than money. In other words, compulsive spenders feel that with credit, they can do anything. Their pleasure in spending enormous amounts is actually greater than the pleasure that they get from the things they buy.
    There is even a special psychology of bargain hunting. To save money, of course, most people look for sales, low prices, and discounts. Compulsive bargain hunters, however, often buy things that they don’t need just because they are cheap. They want to believe that they are helping their budgets, but they are really playing an exciting game: when they can buy something for less than other people, they feel that they are winning. Most people, experts claim, have two reasons for their behavior: a good reason for the things that they do and the real reason.
    It is not only scientists, of course, who understand the psychology of spending habits, but also business-people. Stores, companies and advertisers use psychology to increase business: they consider people’s need for love, power, or influence, their basic values, their beliefs and opinions, and so on in their advertising and sales methods.
    Psychologists often use a method called "behavior therapy" to help individuals solve their personality problems. In the same way, they can help people who feel that they have problems with money.