Hidden costs buyers only discover after booking

What's the real story with all the extra charges that pop up after booking a flat? I just booked a 3BHK with Whiteland in Sector 82A, and the initial quote seemed okay. But now, it feels like every week there's a new demand. PLC, IFMS, club membership, maintenance advance for two years, electricity connection charges... the list just keeps growing. My budget's already stretched, and these aren't small amounts. Honestly, I thought the property price covered most things. Did anyone else face this with Whiteland or other builders in Gurugram? What was your final percentage of extra costs over the base price? Feeling a bit cheated, not gonna lie.