Noida Extension: Hidden costs and negotiation tips?

₹85 lakh for a 2BHK in Sector 145 Laureate Buildwell, and that's just the base price. My wife and I are looking to downsize since the kids have moved out, so we're selling our big house and want something manageable here. But honestly, figuring out the true all-in cost is a headache. Beyond the base, there's stamp duty, registration, PLC, parking, and then I'm hearing about hidden charges that pop up closer to possession. What should I really budget for, beyond the quoted price? Also, does negotiation actually work with builders like Gaurs or Godrej in Noida Extension? I'm not sure if they even budge much on price anymore with the market picking up because of Jewar Airport. Has anyone managed to get a good discount, maybe 5-10%, especially for a spot deal? Or should I just focus on getting some extras thrown in? Any insights on what to look out for in terms of these "hidden charges" would be so helpful.