Dear Dhruv,

I assume that your income is Rs.250000/- per annum (ignoring 80C deduction) if you pay medical insurance for Rs.15000/- then your taxable income will be

Gross Total Income : Rs.250000/-

Less : Deduction u/s 80D : Rs.15000/-

Taxable Income : Rs.235000

Tax on Rs.235000/- is Rs.21000/- so you made a tax saving of Rs.3000/-. (ignoring education cess)