All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
Allaah Almighty has forbidden extravagance and has indicated that He does not like the extravagant. Allaah says (what means):
• {And eat and drink, but be not extravagant. Indeed, He likes not those who commit extravagance.} [Quran 7: 31]
• {And give the relative his right, and [also] the poor and the traveler, and do not spend wastefully. Indeed, the wasteful are brothers of the devils, and ever has Satan been to his Lord ungrateful.} [Quran 17: 26-27]
The verses forbid Muslims to be extravagant by spending on what is unimportant or what is unlawful. Ash-Shaafi‘i said: "Extravagance is to spend wealth unrightfully. Nonetheless, there is no extravagance in doing what is good and righteous."
There is no certain criterion to control buying clothes. Rather, this is determined according to one's financial ability. It happens that a person is reputable among his people and needs to wear expensive clothes. Such a person is not regarded as extravagant. However, another person may be considered extravagant and squanderer if he does the same thing. The Prophet, sallallaahu ‘alayhi wa sallam, said: "Eat, drink, dress and give in charity without extravagance or haughtiness." [An-Nasaa’i and Al-Haakim. Al-Bukhari reported it as a mu‘allaq Hadeeth]
Allaah Knows best.