I'm still a sophomore student. I want to buy iPhone 6S. But it's too expensive for me. Is there any good way to have it with limited money?

You can try the installment payments with your credit card, some cards will offer such services. Or there should be some products for installments even without cards. I know such one. It's a product from TianYao Information, on which you can apply for some credit amount and buy things on its paltform directly. But you'd better make sure you have the money to repay every month.

You can try installment payments. Many credit cards provide such service with low interest rate. Installment is always good for improving cash flow.