Noida Extension: Real all-in cost aur negotiation pe advice?

Sector 110 — kids have moved out, so my wife and I are looking to downsize. Don't need such a big place anymore. Selling our current house, eyeing a compact 2BHK in Noida Extension, maybe around ₹80L-₹1Cr. Rani Promoters ka ek project dekha hai. My main concern is the true all-in cost. Builder log initial price kuch aur batate hain, but baad mein PLC, maintenance advance, registration, parking ke charges add ho jaate hain. Kitna extra expect karna chahiye? Also, negotiation ka kya scene hai? Can we actually get a decent discount, ya bas token amount hi kam hota hai? Should I try negotiating directly with the builder ya broker ke through better deal milegi? Any tips for avoiding hidden charges?