Gurgaon property: All-in cost, kitna extra lagta hai?

Visited a few projects in Sector 93 last weekend, including BST Developers. Honestly, I'm fed up of renting yaar, landlord just hiked rent again. My budget for a 3BHK is around ₹1.5 Cr. But the 'all-in' cost breakdown is so confusing. Builders quote one price, then add stamp duty, registration, PLC, parking... It feels like so many hidden charges only appear later. Is there any way to predict the final amount accurately? Can we even negotiate on these extra costs like stamp duty?