New Delhi builders barely negotiate on new properties

Since January I've been shortlisting flats in this city, fed up of renting. My landlord just raised rent again, so ab finally taking the plunge. Dekh raha hoon Paschim Vihar mein, Swaraj Homes Builders & Developer ke projects bhi dekhe. But yaar, negotiation ka scene kya hai? Builders toh price kam karte hi nahi lagte, 2-3% se zyada toh koi baat hi nahi karta. Kya secondary market mein zyada scope milta hai? Also, all-in cost mein kya-kya hidden charges aate hain? Stamp duty, registration ke alawa aur kya expect karoon? Meri EMI vs rent math tabhi sahi baithegi jab total cost clear ho.