Gurugram property: The real price nobody tells you

Honestly, I'm completely overwhelmed trying to figure out all the actual costs involved in buying property in Gurugram. I'm looking at Signature Global in Sector 4, unka quoted price hai but I'm trying to understand ki kitna negotiation possible hai? Builders bolte hain fixed price, but kya koi real room hota hai? Has anyone managed to get a good spot discount? Aur possession ke time pe kya hidden charges aate hain jo abhi nahi dikhte? Stamp duty, registration ke alawa aur kya add hota hai total cost mein? My goal is to maximise deal value, so any advice on spotting underpriced assets ya payment plan leverage would be super helpful.