Prem Nagar resale: calculating the real cost

Spent the whole Sunday checking out options in Sector 80 online. I'm based in Dubai, so physical site visits are tough. Was looking at a 3BHK resale option near Prem Nagar, maybe Lotus Realtech ka koi project. Broker toh bol raha hai secondary market mein better negotiation scope hai, but all-in cost ka thoda dar lag raha hai. Specifically, stamp duty registration fees kitni hoti hain on resale? Builder se direct deal karne mein kuch difference aata hai kya total acquisition cost mein? Ya broker hi better deal nikalwa deta hai? Not sure if I should trust a broker completely for a POA deal. Any experiences with secondary market deals around SPR? Kya asli mein savings hoti hain after all these charges?