Greater Noida 3BHK: Real cost dilemma?

Two years ago I'd have laughed at these prices, but now I'm seriously looking for a 3BHK in Greater Noida. Pearls Group ka ek project Sector 25 YEIDA mein dekha hai, price ₹90L bol rahe hain. Negotiation kitna possible hai? Matlab, 5-7% off mil sakta hai kya? Hidden charges ka kya scene hai? Suna hai possession ke time maintenance, club, aur PLC jaise extra costs aate hain. Meri wife aur kids ke school ke liye safety first hai, so budget tight rakhna hai. Kitna extra lagta hai on top of quoted price? Any tips to avoid surprises? Hope this helps someone else too.