The real story behind Greater Noida property costs

What's the actual all-in cost for a 2BHK in Greater Noida? I'm finally fed up of renting; landlord hiked rent again, so I'm taking the plunge. Looking at Sector 20, maybe a Skyline Builders project. Builders quote a base price, but then stamp duty, registration, PLC, parking... it's endless. How much can you realistically negotiate off the 'sticker price'? Is 5% achievable or just a token? I'm really worried about hidden charges appearing at possession, like maintenance deposits. That makes EMI vs rent math impossible. Need tips for true final figure upfront, avoiding surprises.