The option of mutual funds serve as the best investment ideas for students, especially for the young college goers.
Bonds also serve as another best choice of small investment plans for students in India.
This is another option that you have in India for students in the form of Cryptocurrency.
It allows a fixed interest rate on your investment (though not on a regular basis) that is saved in a bank account.
Another option for students willing to take risk is the share market.