First home ke liye kitna extra budget rakhoon?

Budget finalised, loan pre-approved — but ab samajh nahi aa raha ki aur kitna lag jayega. I'm looking at Sector 150, maybe Lavish Buildmart ke projects. Builder ne toh ₹78L bola, but I'm sure there's a lot more like stamp duty, registration, interiors... kitna extra pakad ke chalun? Koi hidden costs jo builders nahi batate? Also, site visit pe kya kya check karna chahiye? Koi red flags jo I might miss as a first-timer? Parents bhi bol rahe dhyan se dekhna. Thoda help kar do yaar.