Student loans must first be used to pay for your tuition, room and board. If there is any money leftover, it is yours to spend as you wish. However, it is highly recommended that you use these funds for educational or living expenses, and not entertainment. Other educational expenses could include school supplies, lab supplies, transportation and communication.
For students that are living off campus, your loan would be best utilized to pay rent and for travel back and forth to campus. It is quite possible the extra money was included in the loan for these very purposes.
Ask yourself how a purchase benefits your education. Granted, the money you receive from your student loans is yours, but it is meant to help you further your studies.
Your student loans can also be used to help you purchase a car. If you live far enough away from campus, a car is part of the cost of your education. Maintenance and upkeep could therefore be something student loan dollars are spent on.
The money could also be spent on paying off credit cards. However, you should compare the rates and terms, because the student loan will have to be repaid as well. In most cases, the credit cards will have higher interest rates.