Chandigarh property: Uncovering the real costs?

Sector 24C — been looking at a 3BHK here, but pricing is confusing. I work in real estate, so I know builder ka marketing spin, par apne liye buy karna different hai. Chandigarh mein price negotiation kitna real hai? For a ₹1.5Cr flat in Sector 49 ya Aerocity, kitna realistically knock off kar sakte hain? Builders always say 'fixed price'. Also, hidden charges kya hote hain beyond stamp duty, registration, PLC? Kya unexpected costs possession time pe aate hain? What's your experience with the *true* all-in cost?