Ask your school if it has a computer purchasing program. Some colleges offer computers as part of the tuition, while others may offer discounted computers. If your school has such a program, it may turn out to be the most cost-effective option.
Consider taking out a little extra on your student loan to cover the cost of textbooks and a computer. Most loan terms stipulate that funds can only be used for school-related expenses, but a computer is often considered an acceptable expense. You will need to plan this ahead of time before the start of a new semester to ensure funds are disbursed in time.
Visit computer or electronics stores either in person or online to find out their financing options. Some computer companies such as Apple and Dell offer financing for new computers or discounts to students and educators. Ask about student financing or discounts and be prepared to provide proof of your student status.
If other options are not available, explore the possibility of buying the computer using a credit card. Ensure that you have a high enough credit limit to cover the total cost of the computer and be sure to pay more than the minimum each and every month or you'll still be paying long after this particular computer has become obsolete.