Your behavior is influenced by the background of your culture and the attitude of your society.
Different people buy different clothes depending on their cultural backgrounds.
Social class
The social class you are in can influenced your behavior.
Wealthier people buy high quality clothes for high price, whereas people in lower class could not afford this type of clothing so they buy low quality clothing for cheap price.
reference groups
If you are in a group or organization, your behaviour might be influenced by it. Either because you are trying to follow the trend of your group, or because other members of your group change your behaviour.
family
Your family's beliefs and attitudes are important influences to your behaviours. For example, if your parents don't allow you to wear bright colour shirts when you were young, there would be a less chance of you wearing bright colour shirts comparing to other people.
Personal influences
Your life aspects such as age, job, and gender can also influence you behavior.
People wearing different clothing at different age ranges.