The real negotiation limits in Delhi property

Okay I'll be honest — I completely underestimated how confusing this process is. I'm looking at a 3BHK in East of Kailash, maybe something by Mrigank Enterprise. Their quote is around ₹3.2 Cr, which feels high. My parents keep saying negotiate hard, but I'm not sure if that even works in Delhi's market anymore. What's a realistic discount one can expect? 5%? 10%? And what about hidden charges? I hear about PLC, OC, maintenance corpus, and stuff that pops up right before possession. Is there a way to factor these in early, or do builders just spring them on you? Honestly, I had no idea it'd be this complex. Any advice on negotiating with builders in this range? And what common 'surprises' should I budget for? Ab samajh nahi aa raha, any experiences appreciated.