It really depends on what are your plans after coming out from NS. If you are planning to continue with studies after NS, then I would suggest that you put your money into fixed deposit till you need to use them, or make investments if you are investment savvy.
If it is for long term, then you may look into long term saving instruments or investment as well. Dollar cost averaging is a good way to get started if you are not well versed with investments yet but yet would like better returns than current bank interest rates.