Gurugram property hunt: Hidden costs and pre-launch reality check

Okay I'll be honest — buying property for myself is way harder than selling it for others. I'm checking out projects near Dwarka Expressway, maybe Paras Buildtech. Builder guys always show base price, but possession pe kya hidden charges aate hain? I'm talking about the final bill beyond stamp duty, registration. Kitna extra laga hai logon ka? Also, pre-launch offers ka kya scene hai, is it genuinely cheaper ya just marketing hype for ROI?