First Delhi home: Real costs and negotiation hopes?

Sonepat Road keeps coming up every time I shortlist something, looking at Chaudhary Realtors' projects there. I'm a first-time buyer, totally confused about the real all-in cost for property in Delhi. Is the listed price ever the final price, honestly? I hear about stamp duty, registration, and PLC, but are there other hidden charges that pop up right before possession? My parents keep saying negotiate hard on a 2BHK around ₹1.5 Cr in Delhi, but I'm not sure if builders even budge much these days. What's been your experience with Delhi builders and negotiation tactics?