Ghaziabad property: Negotiation aur hidden costs pe advice?

Madhuban Bapudham mein property dekh raha tha, yaar. Renting se bilkul pak gaya hoon, ab apna ghar lena hai. EMI vs rent math kar raha tha, aur Wall Rock Infratech ka ek project pasand aaya hai. Initial quote 2BHK ke liye ₹72L diya hai. Builders Ghaziabad mein kitna negotiate karte hain? Matlab, 5-7% ka scope hota hai kya, ya woh sirf bolte hain 'fixed price'? Aur ye all-in cost ka kya scene hai? Stamp duty, registration, PLC, parking... sab milake kitna extra pakad ke chalun? Log bolte hain possession ke time pe kuch hidden charges aate hain. Has anyone else faced this with Ghaziabad builders? Don't want any last-minute surprises. Kya negotiation tactics kaam karti hain?