Gurugram property: Your negotiation wins and hidden costs?

Pataudi Road area — trying to figure out if it's the right move for us. My wife's really focused on schools for the kids, and we need at least a 3BHK for our growing family. We've seen some Vatika Group projects, and while the prices for a 3BHK are around 2.5-3 Cr, I'm honestly not sure how much wiggle room there is. Is price negotiation even a thing in Gurugram, or do builders stick to their rates? How much can one realistically expect to negotiate off the listed price? Also, trying to get a clear picture on the 'all-in' cost. Beyond the base price, what are the usual hidden charges or significant extras like PLC, parking, and maintenance deposits that add up before possession? Don't want any surprises when it's time to sign. Any experiences on what percentage these often add up to?