What hidden charges truly hit you at possession in Noida Extension?

What are the actual hidden charges people got hit with at possession in Noida Extension? Just got my 2BHK in Sector 150 last month, and honestly, the 'all-inclusive' price turned out to be a bit of a myth. There was a surprise 'maintenance corpus fund' and an unexpected 'club membership fee' that weren't clearly itemized during booking. My EMI is already tight, so this extra ₹1.5L was a shocker. I booked during pre-launch hoping for a better deal, but feeling like these last-minute charges negated some of that. Did anyone else face this with builders like Gaursons or ACE? Are there specific clauses to watch out for in the builder-buyer agreement that hint at these extra costs? Trying to figure out how to warn others. Any tips on negotiating these post-booking charges?