Omicron III 2BHK: Real negotiation possible?

Rents went up 15% again this year, honestly I'm fed up of renting. I'm finally looking to buy in Greater Noida, maybe Omicron III for a 2BHK. One Leaf Group has some projects there. Prices are around ₹75-80 lakh. My main question is, how much negotiation is even possible here? Builders always quote high. And what about all the hidden charges? PLC, parking, OC... I don't want surprises later. What's the *real* total cost for an investor to look out for? Any tips?