The first thing to remember is that sometimes there is no clear psychology behind a person’s motivation to purchase. Sometimes it is a number of factors that causes people to buy. Sometimes it is things beyond their control such as external pressures. Other times it is simply a matter of having the means to purchase. How many people have bought “any old thing” from eBay because they have $5 left in Paypal? How many people have bought junk they don’t need on their birthday, because they received some money in their cards?

This article only covers some of the generalizations in psychology. You have to remember that psychology is not a strict science. It creates answers in the form of theories that are incredibly subjective and can only ever be proved one person at a time. For example you cannot say that all people are afraid of spiders because your test group of seven people happens to be afraid of them.