Construction for self use - benefits?

Hi all, I along with one of my relative wants to buy a flat/builder floor in Gurgaon sectors. However, having felt that the initial asking rates are very high, we plan to buy a plot and get two floors constructed in our own way and may be sell the third (2nd floor).

I am not aware of the exact cost savings (if any) that can be achieved in case we build our own house in any of the huda sectors. Experienced members please shed some light broadly on the issues involved and expected costs/savings.