Rent hiked, what's the real deal in Noida Extension?

Landlord just hiked rent again, so I'm finally taking the plunge into buying in Noida Extension. Everyone talks about negotiation, but honestly, does it even work anymore? I'm looking at a 2BHK in Sector 143B, maybe something from Irish Infrastructure. They quote ₹78L but is there any real wiggle room, like 5-7% off, or is that just wishful thinking? I'm also worried about hidden charges at possession. Are there always these surprise fees for things like society formation or extra utility connections that just pop up? Change my mind if I'm wrong.