My first property in E-City: Budget ka shock

Did a site visit to Keya Homes in Electronic City Phase II last weekend. Book kiya tha, but ab pata chal raha kitne extra costs hain. Initial quote mein toh bas basic price dikha rahe the. Super area aur carpet area ka difference ab samajh aa raha hai, it's huge. Stamp duty, registration, interiors... sab milake budget hil gaya hai. Yeh hidden costs ka koi idea nahi tha. Anyone else faced this with builders? How did you manage? Ab samajh nahi aa raha kaise adjust karoon.